diff --git a/animation-worklet/stateful-animator.https.html b/animation-worklet/stateful-animator.https.html
index dba3aa8dc8dfa6..b83590650b1975 100644
--- a/animation-worklet/stateful-animator.https.html
+++ b/animation-worklet/stateful-animator.https.html
@@ -89,7 +89,7 @@
       effect.localTime = this.test_local_time++;
     }
     state() {
-      return new Error('foo');
+      return new Symbol('foo');
     }
   });
 </script>
diff --git a/html/browsers/history/the-history-interface/001.html b/html/browsers/history/the-history-interface/001.html
index 7273593547964e..ac8c8000777474 100644
--- a/html/browsers/history/the-history-interface/001.html
+++ b/html/browsers/history/the-history-interface/001.html
@@ -175,11 +175,10 @@
         }, 'pushState must not be able to use a DOM node as data');
         test(function () {
             try { a.b = c; } catch(errdata) {
-                assert_throws( 'DATA_CLONE_ERR', function () {
-                    history.pushState({dummy:errdata},'');
-                } );
+                history.pushState({dummy:errdata},'');
+                assert_equals(ReferenceError.prototype, Object.getPrototypeOf(history.state.dummy));
             }
-        }, 'pushState must not be able to use an error object as data');
+        }, 'pushState must be able to use an error object as data');
         test(function () {
             assert_throws( 'DATA_CLONE_ERR', function () {
                 iframe.contentWindow.history.pushState(document,'');
diff --git a/html/browsers/history/the-history-interface/002.html b/html/browsers/history/the-history-interface/002.html
index c5bae3407c8998..431f6a58634f9d 100644
--- a/html/browsers/history/the-history-interface/002.html
+++ b/html/browsers/history/the-history-interface/002.html
@@ -156,11 +156,10 @@
         }, 'replaceState must not be able to use a DOM node as data');
         test(function () {
             try { a.b = c; } catch(errdata) {
-                assert_throws( 'DATA_CLONE_ERR', function () {
-                    history.replaceState({dummy:errdata},'');
-                } );
+                history.replaceState({dummy:errdata},'');
+                assert_equals(ReferenceError.prototype, Object.getPrototypeOf(history.state.dummy));
             }
-        }, 'replaceState must not be able to use an error object as data');
+        }, 'replaceState must be able to use an error object as data');
         test(function () {
             assert_throws( 'DATA_CLONE_ERR', function () {
                 iframe.contentWindow.history.replaceState(document,'');