diff --git a/.forge-snapshots/Base-V3DutchOrder-BaseExecuteSingleWithFee.snap b/.forge-snapshots/Base-V3DutchOrder-BaseExecuteSingleWithFee.snap
index 4189ab1c..5cd8344c 100644
--- a/.forge-snapshots/Base-V3DutchOrder-BaseExecuteSingleWithFee.snap
+++ b/.forge-snapshots/Base-V3DutchOrder-BaseExecuteSingleWithFee.snap
@@ -1 +1 @@
-198680
\ No newline at end of file
+199172
\ No newline at end of file
diff --git a/.forge-snapshots/Base-V3DutchOrder-ExecuteBatch.snap b/.forge-snapshots/Base-V3DutchOrder-ExecuteBatch.snap
index 6d9b5398..26009a86 100644
--- a/.forge-snapshots/Base-V3DutchOrder-ExecuteBatch.snap
+++ b/.forge-snapshots/Base-V3DutchOrder-ExecuteBatch.snap
@@ -1 +1 @@
-230916
\ No newline at end of file
+231968
\ No newline at end of file
diff --git a/.forge-snapshots/Base-V3DutchOrder-ExecuteBatchMultipleOutputs.snap b/.forge-snapshots/Base-V3DutchOrder-ExecuteBatchMultipleOutputs.snap
index db264c79..9540249d 100644
--- a/.forge-snapshots/Base-V3DutchOrder-ExecuteBatchMultipleOutputs.snap
+++ b/.forge-snapshots/Base-V3DutchOrder-ExecuteBatchMultipleOutputs.snap
@@ -1 +1 @@
-244376
\ No newline at end of file
+245818
\ No newline at end of file
diff --git a/.forge-snapshots/Base-V3DutchOrder-ExecuteBatchMultipleOutputsDifferentTokens.snap b/.forge-snapshots/Base-V3DutchOrder-ExecuteBatchMultipleOutputsDifferentTokens.snap
index 5fa802f2..432d427d 100644
--- a/.forge-snapshots/Base-V3DutchOrder-ExecuteBatchMultipleOutputsDifferentTokens.snap
+++ b/.forge-snapshots/Base-V3DutchOrder-ExecuteBatchMultipleOutputsDifferentTokens.snap
@@ -1 +1 @@
-301741
\ No newline at end of file
+303592
\ No newline at end of file
diff --git a/.forge-snapshots/Base-V3DutchOrder-ExecuteBatchNativeOutput.snap b/.forge-snapshots/Base-V3DutchOrder-ExecuteBatchNativeOutput.snap
index 18ceec9a..e97b81f9 100644
--- a/.forge-snapshots/Base-V3DutchOrder-ExecuteBatchNativeOutput.snap
+++ b/.forge-snapshots/Base-V3DutchOrder-ExecuteBatchNativeOutput.snap
@@ -1 +1 @@
-224442
\ No newline at end of file
+225494
\ No newline at end of file
diff --git a/.forge-snapshots/Base-V3DutchOrder-ExecuteSingle.snap b/.forge-snapshots/Base-V3DutchOrder-ExecuteSingle.snap
index dac86684..9cee8b71 100644
--- a/.forge-snapshots/Base-V3DutchOrder-ExecuteSingle.snap
+++ b/.forge-snapshots/Base-V3DutchOrder-ExecuteSingle.snap
@@ -1 +1 @@
-165065
\ No newline at end of file
+165555
\ No newline at end of file
diff --git a/.forge-snapshots/Base-V3DutchOrder-ExecuteSingleNativeOutput.snap b/.forge-snapshots/Base-V3DutchOrder-ExecuteSingleNativeOutput.snap
index 462a84ec..7ae7e611 100644
--- a/.forge-snapshots/Base-V3DutchOrder-ExecuteSingleNativeOutput.snap
+++ b/.forge-snapshots/Base-V3DutchOrder-ExecuteSingleNativeOutput.snap
@@ -1 +1 @@
-150627
\ No newline at end of file
+151117
\ No newline at end of file
diff --git a/.forge-snapshots/Base-V3DutchOrder-ExecuteSingleValidation.snap b/.forge-snapshots/Base-V3DutchOrder-ExecuteSingleValidation.snap
index 1bf89fbb..188a54c0 100644
--- a/.forge-snapshots/Base-V3DutchOrder-ExecuteSingleValidation.snap
+++ b/.forge-snapshots/Base-V3DutchOrder-ExecuteSingleValidation.snap
@@ -1 +1 @@
-174381
\ No newline at end of file
+174866
\ No newline at end of file
diff --git a/.forge-snapshots/Base-V3DutchOrder-RevertInvalidNonce.snap b/.forge-snapshots/Base-V3DutchOrder-RevertInvalidNonce.snap
index c7b7e542..e5308bcc 100644
--- a/.forge-snapshots/Base-V3DutchOrder-RevertInvalidNonce.snap
+++ b/.forge-snapshots/Base-V3DutchOrder-RevertInvalidNonce.snap
@@ -1 +1 @@
-43685
\ No newline at end of file
+44191
\ No newline at end of file
diff --git a/.forge-snapshots/Base-V3DutchOrder-V3-ExclusiveFiller.snap b/.forge-snapshots/Base-V3DutchOrder-V3-ExclusiveFiller.snap
index 751f1997..78251840 100644
--- a/.forge-snapshots/Base-V3DutchOrder-V3-ExclusiveFiller.snap
+++ b/.forge-snapshots/Base-V3DutchOrder-V3-ExclusiveFiller.snap
@@ -1 +1 @@
-168989
\ No newline at end of file
+169490
\ No newline at end of file
diff --git a/.forge-snapshots/Base-V3DutchOrder-V3-InputOverride.snap b/.forge-snapshots/Base-V3DutchOrder-V3-InputOverride.snap
index 1b58f6bb..c5c65d5c 100644
--- a/.forge-snapshots/Base-V3DutchOrder-V3-InputOverride.snap
+++ b/.forge-snapshots/Base-V3DutchOrder-V3-InputOverride.snap
@@ -1 +1 @@
-169070
\ No newline at end of file
+169571
\ No newline at end of file
diff --git a/.forge-snapshots/Base-V3DutchOrder-V3-OutputOverride.snap b/.forge-snapshots/Base-V3DutchOrder-V3-OutputOverride.snap
index 8514e5c2..f1a4bb72 100644
--- a/.forge-snapshots/Base-V3DutchOrder-V3-OutputOverride.snap
+++ b/.forge-snapshots/Base-V3DutchOrder-V3-OutputOverride.snap
@@ -1 +1 @@
-169013
\ No newline at end of file
+169514
\ No newline at end of file
diff --git a/.forge-snapshots/V3-DutchDecay.snap b/.forge-snapshots/V3-DutchDecay.snap
index 2b163bad..284a734f 100644
--- a/.forge-snapshots/V3-DutchDecay.snap
+++ b/.forge-snapshots/V3-DutchDecay.snap
@@ -1 +1 @@
-13179
\ No newline at end of file
+13371
\ No newline at end of file
diff --git a/.forge-snapshots/V3-DutchDecayBounded.snap b/.forge-snapshots/V3-DutchDecayBounded.snap
index 1f168c59..77e48ce7 100644
--- a/.forge-snapshots/V3-DutchDecayBounded.snap
+++ b/.forge-snapshots/V3-DutchDecayBounded.snap
@@ -1 +1 @@
-1199
\ No newline at end of file
+1193
\ No newline at end of file
diff --git a/.forge-snapshots/V3-DutchDecayFullyDecayed.snap b/.forge-snapshots/V3-DutchDecayFullyDecayed.snap
index e5e37b03..e2b27312 100644
--- a/.forge-snapshots/V3-DutchDecayFullyDecayed.snap
+++ b/.forge-snapshots/V3-DutchDecayFullyDecayed.snap
@@ -1 +1 @@
-6677
\ No newline at end of file
+6779
\ No newline at end of file
diff --git a/.forge-snapshots/V3-DutchDecayFullyDecayedNegative.snap b/.forge-snapshots/V3-DutchDecayFullyDecayedNegative.snap
index 50d06af6..67e488ea 100644
--- a/.forge-snapshots/V3-DutchDecayFullyDecayedNegative.snap
+++ b/.forge-snapshots/V3-DutchDecayFullyDecayedNegative.snap
@@ -1 +1 @@
-6365
\ No newline at end of file
+6467
\ No newline at end of file
diff --git a/.forge-snapshots/V3-DutchDecayNegative.snap b/.forge-snapshots/V3-DutchDecayNegative.snap
index 11b9a892..34201494 100644
--- a/.forge-snapshots/V3-DutchDecayNegative.snap
+++ b/.forge-snapshots/V3-DutchDecayNegative.snap
@@ -1 +1 @@
-1271
\ No newline at end of file
+1265
\ No newline at end of file
diff --git a/.forge-snapshots/V3-DutchDecayNoDecayYet.snap b/.forge-snapshots/V3-DutchDecayNoDecayYet.snap
index 9b08816d..222192ce 100644
--- a/.forge-snapshots/V3-DutchDecayNoDecayYet.snap
+++ b/.forge-snapshots/V3-DutchDecayNoDecayYet.snap
@@ -1 +1 @@
-4703
\ No newline at end of file
+4697
\ No newline at end of file
diff --git a/.forge-snapshots/V3-DutchDecayNoDecayYetNegative.snap b/.forge-snapshots/V3-DutchDecayNoDecayYetNegative.snap
index 9b08816d..222192ce 100644
--- a/.forge-snapshots/V3-DutchDecayNoDecayYetNegative.snap
+++ b/.forge-snapshots/V3-DutchDecayNoDecayYetNegative.snap
@@ -1 +1 @@
-4703
\ No newline at end of file
+4697
\ No newline at end of file
diff --git a/.forge-snapshots/V3-DutchDecayRange.snap b/.forge-snapshots/V3-DutchDecayRange.snap
index 11b9a892..34201494 100644
--- a/.forge-snapshots/V3-DutchDecayRange.snap
+++ b/.forge-snapshots/V3-DutchDecayRange.snap
@@ -1 +1 @@
-1271
\ No newline at end of file
+1265
\ No newline at end of file
diff --git a/.forge-snapshots/V3-ExtendedMultiPointDutchDecay.snap b/.forge-snapshots/V3-ExtendedMultiPointDutchDecay.snap
index c1250b2e..6dffa512 100644
--- a/.forge-snapshots/V3-ExtendedMultiPointDutchDecay.snap
+++ b/.forge-snapshots/V3-ExtendedMultiPointDutchDecay.snap
@@ -1 +1 @@
-88354
\ No newline at end of file
+88450
\ No newline at end of file
diff --git a/.forge-snapshots/V3-LocateCurvePositionMulti.snap b/.forge-snapshots/V3-LocateCurvePositionMulti.snap
index 73b08ba1..958c8b94 100644
--- a/.forge-snapshots/V3-LocateCurvePositionMulti.snap
+++ b/.forge-snapshots/V3-LocateCurvePositionMulti.snap
@@ -1 +1 @@
-20492
\ No newline at end of file
+20330
\ No newline at end of file
diff --git a/.forge-snapshots/V3-LocateCurvePositionSingle.snap b/.forge-snapshots/V3-LocateCurvePositionSingle.snap
index 9726dc60..4a2277e6 100644
--- a/.forge-snapshots/V3-LocateCurvePositionSingle.snap
+++ b/.forge-snapshots/V3-LocateCurvePositionSingle.snap
@@ -1 +1 @@
-6860
\ No newline at end of file
+6830
\ No newline at end of file
diff --git a/.forge-snapshots/V3-MultiPointDutchDecay.snap b/.forge-snapshots/V3-MultiPointDutchDecay.snap
index 81237bad..1a263175 100644
--- a/.forge-snapshots/V3-MultiPointDutchDecay.snap
+++ b/.forge-snapshots/V3-MultiPointDutchDecay.snap
@@ -1 +1 @@
-26242
\ No newline at end of file
+26539
\ No newline at end of file
diff --git a/src/lib/MathExt.sol b/src/lib/MathExt.sol
index 02a2a786..89bdf494 100644
--- a/src/lib/MathExt.sol
+++ b/src/lib/MathExt.sol
@@ -23,6 +23,7 @@ library MathExt {
     /// @param min The minimum bound for the result.
     /// @param max The maximum bound for the result.
     /// @return r The result of the bounded addition.
+    /// @dev This function reverts when `b == type(int256).min` due to integer overflow.
     function boundedAdd(uint256 a, int256 b, uint256 min, uint256 max) internal pure returns (uint256 r) {
         r = boundedSub(a, 0 - b, min, max);
     }
@@ -33,6 +34,7 @@ library MathExt {
     /// @param min The minimum bound for the result.
     /// @param max The maximum bound for the result.
     /// @return r The result of the bounded subtraction.
+    /// @dev This function reverts when `b == type(int256).min` due to integer overflow.
     function boundedSub(uint256 a, int256 b, uint256 min, uint256 max) internal pure returns (uint256 r) {
         if (b < 0) {
             // If b is negative, add its absolute value to a
diff --git a/src/lib/NonlinearDutchDecayLib.sol b/src/lib/NonlinearDutchDecayLib.sol
index b979a883..bdeaa5f1 100644
--- a/src/lib/NonlinearDutchDecayLib.sol
+++ b/src/lib/NonlinearDutchDecayLib.sol
@@ -5,6 +5,7 @@ import {OutputToken, InputToken} from "../base/ReactorStructs.sol";
 import {V3DutchOutput, V3DutchInput, NonlinearDutchDecay} from "../lib/V3DutchOrderLib.sol";
 import {FixedPointMathLib} from "solmate/src/utils/FixedPointMathLib.sol";
 import {MathExt} from "./MathExt.sol";
+import {Math} from "openzeppelin-contracts/utils/math/Math.sol";
 import {Uint16ArrayLibrary, Uint16Array, fromUnderlying} from "../types/Uint16Array.sol";
 import {DutchDecayLib} from "./DutchDecayLib.sol";
 
@@ -17,11 +18,12 @@ library NonlinearDutchDecayLib {
     /// @notice thrown when the decay curve is invalid
     error InvalidDecayCurve();
 
-    /// @notice locates the current position on the curve and calculates the decay
-    /// @param curve The curve to search
-    /// @param startAmount The absolute start amount
-    /// @param decayStartBlock The absolute start block of the decay
+    /// @notice Calculates the decayed amount based on the current block and the defined curve
+    /// @param curve The nonlinear decay curve definition
+    /// @param startAmount The initial amount at the start of the decay
+    /// @param decayStartBlock The absolute block number when the decay begins
     /// @dev Expects the relativeBlocks in curve to be strictly increasing
+    /// @return decayedAmount The amount after applying the decay, bounded by minAmount and maxAmount
     function decay(
         NonlinearDutchDecay memory curve,
         uint256 startAmount,
@@ -38,8 +40,9 @@ library NonlinearDutchDecayLib {
         if (decayStartBlock >= block.number || curve.relativeAmounts.length == 0) {
             return startAmount.bound(minAmount, maxAmount);
         }
-
-        uint16 blockDelta = uint16(block.number - decayStartBlock);
+        // If the blockDelta is larger than type(uint16).max, a downcast overflow will occur
+        // We prevent this by capping the blockDelta to type(uint16).max to express a full decay
+        uint16 blockDelta = uint16(Math.min(block.number - decayStartBlock, type(uint16).max));
         (uint16 startPoint, uint16 endPoint, int256 relStartAmount, int256 relEndAmount) =
             locateCurvePosition(curve, blockDelta);
         // get decay of only the relative amounts
@@ -48,13 +51,16 @@ library NonlinearDutchDecayLib {
         return startAmount.boundedSub(curveDelta, minAmount, maxAmount);
     }
 
-    /// @notice Locates the current position on the curve
-    /// @param curve The curve to search
-    /// @param currentRelativeBlock The current relative position
-    /// @return startPoint The relative block before the current position
-    /// @return endPoint The relative block after the current position
-    /// @return startAmount The relative amount before the current position
-    /// @return endAmount The relative amount after the current position
+    /// @notice Locates the current position on the decay curve based on the elapsed blocks
+    /// @param curve The nonlinear decay curve definition
+    /// @param currentRelativeBlock The number of blocks elapsed since decayStartBlock
+    /// @return startPoint The relative block number of the previous curve point
+    /// @return endPoint The relative block number of the next curve point
+    /// @return startAmount The relative change from initial amount at the previous curve point
+    /// @return endAmount The relative change from initial amount at the next curve point
+    /// @dev The returned amounts are changes relative to the initial startAmount, not absolute values
+    /// @dev If currentRelativeBlock is before the first curve point, startPoint and startAmount will be 0
+    /// @dev If currentRelativeBlock is after the last curve point, both points will be the last curve point
     function locateCurvePosition(NonlinearDutchDecay memory curve, uint16 currentRelativeBlock)
         internal
         pure
diff --git a/src/lib/V3DutchOrderLib.sol b/src/lib/V3DutchOrderLib.sol
index 41798218..38cef7e4 100644
--- a/src/lib/V3DutchOrderLib.sol
+++ b/src/lib/V3DutchOrderLib.sol
@@ -95,7 +95,8 @@ library V3DutchOrderLib {
         "uint256 maxAmount,",
         "uint256 adjustmentPerGweiBaseFee)"
     );
-    bytes32 internal constant V3_DUTCH_INPUT_TYPE_HASH = keccak256(V3_DUTCH_INPUT_TYPE);
+    bytes32 internal constant V3_DUTCH_INPUT_TYPE_HASH =
+        keccak256(abi.encodePacked(V3_DUTCH_INPUT_TYPE, NON_LINEAR_DECAY_TYPE));
     bytes internal constant V3_DUTCH_OUTPUT_TYPE = abi.encodePacked(
         "V3DutchOutput(",
         "address token,",
@@ -105,7 +106,8 @@ library V3DutchOrderLib {
         "uint256 minAmount,",
         "uint256 adjustmentPerGweiBaseFee)"
     );
-    bytes32 internal constant V3_DUTCH_OUTPUT_TYPE_HASH = keccak256(V3_DUTCH_OUTPUT_TYPE);
+    bytes32 internal constant V3_DUTCH_OUTPUT_TYPE_HASH =
+        keccak256(abi.encodePacked(V3_DUTCH_OUTPUT_TYPE, NON_LINEAR_DECAY_TYPE));
     bytes internal constant NON_LINEAR_DECAY_TYPE =
         abi.encodePacked("NonlinearDutchDecay(", "uint256 relativeBlocks,", "int256[] relativeAmounts)");
     bytes32 internal constant NON_LINEAR_DECAY_TYPE_HASH = keccak256(NON_LINEAR_DECAY_TYPE);
@@ -208,9 +210,9 @@ library V3DutchOrderLib {
     }
 
     /// @notice get the digest of the cosigner data
-    /// @param order the priorityOrder
+    /// @param order the V3DutchOrder
     /// @param orderHash the hash of the order
-    function cosignerDigest(V3DutchOrder memory order, bytes32 orderHash) internal pure returns (bytes32) {
-        return keccak256(abi.encodePacked(orderHash, abi.encode(order.cosignerData)));
+    function cosignerDigest(V3DutchOrder memory order, bytes32 orderHash) internal view returns (bytes32) {
+        return keccak256(abi.encodePacked(orderHash, block.chainid, abi.encode(order.cosignerData)));
     }
 }
diff --git a/src/reactors/V3DutchOrderReactor.sol b/src/reactors/V3DutchOrderReactor.sol
index ac20f2a6..afdd46cf 100644
--- a/src/reactors/V3DutchOrderReactor.sol
+++ b/src/reactors/V3DutchOrderReactor.sol
@@ -14,7 +14,7 @@ import {Math} from "openzeppelin-contracts/utils/math/Math.sol";
 import {CosignerLib} from "../lib/CosignerLib.sol";
 
 /// @notice Reactor for V3 dutch orders
-/// @dev V3 orders must be cosigned by the specified cosigner to override starting block and value
+/// @dev V3 orders must be cosigned by the specified cosigner to set the starting block and override the value
 /// @dev resolution behavior:
 /// - If cosignature is invalid or not from specified cosigner, revert
 /// - If inputAmount is 0, then use baseInput
@@ -111,17 +111,21 @@ contract V3DutchOrderReactor is BaseReactor {
     function _updateWithGasAdjustment(V3DutchOrder memory order) internal view {
         // Positive means an increase in gas
         int256 gasDeltaWei = block.basefee.sub(order.startingBaseFee);
-
-        // Round in favor of swapper
-        int256 inputDelta = _computeDelta(order.baseInput.adjustmentPerGweiBaseFee, gasDeltaWei);
-        order.baseInput.startAmount = order.baseInput.startAmount.boundedAdd(inputDelta, 0, order.baseInput.maxAmount);
-
+        // Gas increase should increase input
+        if (order.baseInput.adjustmentPerGweiBaseFee != 0) {
+            // Round in favor of swapper
+            int256 inputDelta = _computeDelta(order.baseInput.adjustmentPerGweiBaseFee, gasDeltaWei);
+            order.baseInput.startAmount = order.baseInput.startAmount.boundedAdd(inputDelta, 0, order.baseInput.maxAmount);
+        }
+        // Gas increase should decrease output
         uint256 outputsLength = order.baseOutputs.length;
         for (uint256 i = 0; i < outputsLength; i++) {
             V3DutchOutput memory output = order.baseOutputs[i];
-            // Round in favor of swapper
-            int256 outputDelta = _computeDelta(output.adjustmentPerGweiBaseFee, gasDeltaWei);
-            output.startAmount = output.startAmount.boundedSub(outputDelta, output.minAmount, type(uint256).max);
+            if (output.adjustmentPerGweiBaseFee != 0) {
+                // Round in favor of swapper
+                int256 outputDelta = _computeDelta(output.adjustmentPerGweiBaseFee, gasDeltaWei);
+                output.startAmount = output.startAmount.boundedSub(outputDelta, output.minAmount, type(uint256).max);
+            }
         }
     }
 
@@ -137,7 +141,7 @@ contract V3DutchOrderReactor is BaseReactor {
 
     /// @notice validate the dutch order fields
     /// - deadline must have not passed
-    /// - cosigner is valid if specified
+    /// - cosigner must always be provided and sign the cosignerData
     /// @dev Throws if the order is invalid
     function _validateOrder(bytes32 orderHash, V3DutchOrder memory order) internal view {
         if (order.info.deadline < block.timestamp) {
diff --git a/src/types/Uint16Array.sol b/src/types/Uint16Array.sol
index 0ecb75a7..61438038 100644
--- a/src/types/Uint16Array.sol
+++ b/src/types/Uint16Array.sol
@@ -37,7 +37,7 @@ library Uint16ArrayLibrary {
         }
         unchecked {
             uint256 shiftAmount = n * 16;
-            uint16 result = uint16((Uint16Array.unwrap(packedData) >> shiftAmount) & 0xFFFF);
+            uint16 result = uint16(Uint16Array.unwrap(packedData) >> shiftAmount);
             return result;
         }
     }
diff --git a/test/lib/EIP712.t.sol b/test/lib/EIP712.t.sol
new file mode 100644
index 00000000..2b74e690
--- /dev/null
+++ b/test/lib/EIP712.t.sol
@@ -0,0 +1,46 @@
+import {Test} from "forge-std/Test.sol";
+import {NonlinearDutchDecay, V3DutchOrderLib, V3DutchOutput} from "../../src/lib/V3DutchOrderLib.sol";
+
+contract EIP712Test is Test {
+    function test_NonlinearDutchDecayHash() public pure {
+        assertEq(
+            V3DutchOrderLib.NON_LINEAR_DECAY_TYPE_HASH,
+            hex"30c39ae6ecb284279579f99803ba5d7b54275a8a6a04180056b5031b8c19a01a"
+        );
+
+        int256[] memory amounts = new int256[](1);
+        amounts[0] = 1;
+        NonlinearDutchDecay memory curve = NonlinearDutchDecay(1, amounts);
+        assertEq(V3DutchOrderLib.hash(curve), hex"ad28931e960b684a49cdf1aca21bd966df5bac39996c5a0615c0a54f2f22a06f");
+    }
+
+    function test_V3DutchInputHash() public pure {
+        assertEq(
+            V3DutchOrderLib.V3_DUTCH_INPUT_TYPE_HASH,
+            hex"2cc4ccc271072d8b406616a16a6e9a3935dea10f0eb920f44737e1855ecc68eb"
+        );
+    }
+
+    function test_V3DutchOutputHash() public pure {
+        assertEq(
+            V3DutchOrderLib.V3_DUTCH_OUTPUT_TYPE_HASH,
+            hex"7fd857ffad1736e72f90e17c9d15cabe562b86b45c6e618ae0e7fa92c4a6fde9"
+        );
+
+        address token = address(0);
+        uint256 startAmount = 21;
+        int256[] memory amounts = new int256[](1);
+        amounts[0] = 1;
+        NonlinearDutchDecay memory curve = NonlinearDutchDecay(1, amounts);
+        address recipient = address(0);
+        uint256 minAmount = 20;
+        uint256 adjustmentPerGweiBaseFee = 0;
+        V3DutchOutput memory output =
+            V3DutchOutput(token, startAmount, curve, recipient, minAmount, adjustmentPerGweiBaseFee);
+        assertEq(V3DutchOrderLib.hash(output), hex"c57ac5e0436939ec593af412dde4a05d4972a0a8a56bbdb63ca7cd949c5326e2");
+    }
+
+    function test_OrderTypeHash() public pure {
+        assertEq(V3DutchOrderLib.ORDER_TYPE_HASH, hex"186c8af0344af94faab60c9dc413f68b8ca7aea1aded04a300c7fa35562ed1b7");
+    }
+}
diff --git a/test/lib/NonLinearDutchDecayLib.t.sol b/test/lib/NonLinearDutchDecayLib.t.sol
index c4217418..8fa6c522 100644
--- a/test/lib/NonLinearDutchDecayLib.t.sol
+++ b/test/lib/NonLinearDutchDecayLib.t.sol
@@ -8,6 +8,7 @@ import {DutchDecayLib} from "../../src/lib/DutchDecayLib.sol";
 import {NonlinearDutchDecayLib} from "../../src/lib/NonlinearDutchDecayLib.sol";
 import {V3DutchOutput, V3DutchInput, NonlinearDutchDecay} from "../../src/lib/V3DutchOrderLib.sol";
 import {Uint16Array, toUint256} from "../../src/types/Uint16Array.sol";
+import {Math} from "openzeppelin-contracts/utils/math/Math.sol";
 import {ArrayBuilder} from "../util/ArrayBuilder.sol";
 import {CurveBuilder} from "../util/CurveBuilder.sol";
 
@@ -474,4 +475,44 @@ contract NonlinearDutchDecayLibTest is Test, GasSnapshot {
         vm.expectRevert(NonlinearDutchDecayLib.InvalidDecayCurve.selector);
         mockNonlinearDutchDecayLibContract.decay(curve, startAmount, decayStartBlock, 1 ether, 1 ether);
     }
+
+    function testFuzzDutchDecayBeyondUint16Max(
+        uint16 lastValidBlock, // For curve
+        uint256 decayAmountFuzz, // For curve
+        // decay(curve, startAmount, decayStartBlock, minAmount, maxAmount);
+        uint256 startAmount,
+        uint256 decayStartBlock,
+        uint256 minAmount,
+        uint256 maxAmount,
+        uint256 currentBlock
+    ) public {
+        vm.assume(decayStartBlock < type(uint256).max - type(uint16).max);
+        vm.assume(lastValidBlock > 0);
+        vm.assume(startAmount > 0 && startAmount < uint256(type(int256).max));
+        vm.assume(maxAmount >= startAmount);
+        minAmount = bound(minAmount, 0, startAmount);
+        // bound only takes uint256, so we need to limit decayAmountFuzz to int256.max
+        // because we cast it to int256 in the decay function
+        decayAmountFuzz = bound(decayAmountFuzz, minAmount, startAmount);
+
+        // Testing that we get a fully decayed curve instead of overflowed mistake
+        // This will happen when the block delta is larger than type(uint16).max
+        vm.assume(currentBlock > decayStartBlock + type(uint16).max);
+
+        uint16[] memory blocks = new uint16[](1);
+        blocks[0] = lastValidBlock;
+
+        int256[] memory decayAmounts = new int256[](1);
+        decayAmounts[0] = int256(decayAmountFuzz);
+
+        NonlinearDutchDecay memory curve = CurveBuilder.multiPointCurve(blocks, decayAmounts);
+
+        vm.roll(currentBlock);
+        uint256 decayed = NonlinearDutchDecayLib.decay(curve, startAmount, decayStartBlock, minAmount, maxAmount);
+        assertEq(
+            decayed,
+            Math.max(startAmount - decayAmountFuzz, minAmount),
+            "Should be fully decayed for block delta beyond uint16.max"
+        );
+    }
 }
diff --git a/test/reactors/V3DutchOrderReactor.t.sol b/test/reactors/V3DutchOrderReactor.t.sol
index fed2cf70..694cca03 100644
--- a/test/reactors/V3DutchOrderReactor.t.sol
+++ b/test/reactors/V3DutchOrderReactor.t.sol
@@ -1501,8 +1501,8 @@ contract V3DutchOrderTest is PermitSignature, DeployPermit2, BaseReactorTest {
         (order,) = createAndSignDutchOrder(request);
     }
 
-    function cosignOrder(bytes32 orderHash, CosignerData memory cosignerData) private pure returns (bytes memory sig) {
-        bytes32 msgHash = keccak256(abi.encodePacked(orderHash, abi.encode(cosignerData)));
+    function cosignOrder(bytes32 orderHash, CosignerData memory cosignerData) private view returns (bytes memory sig) {
+        bytes32 msgHash = keccak256(abi.encodePacked(orderHash, block.chainid, abi.encode(cosignerData)));
         (uint8 v, bytes32 r, bytes32 s) = vm.sign(cosignerPrivateKey, msgHash);
         sig = bytes.concat(r, s, bytes1(v));
     }