diff --git a/src/fallback.ts b/src/fallback.ts
index 19c5cbfcd..aae307ab0 100644
--- a/src/fallback.ts
+++ b/src/fallback.ts
@@ -28,7 +28,6 @@ import {
   GoogleAuthOptions,
   BaseExternalAccountClient,
 } from 'google-auth-library';
-import * as objectHash from 'object-hash';
 import {OperationsClientBuilder} from './operationsClient';
 import {GrpcClientOptions, ClientStubOptions} from './grpc';
 import {GaxCall, GRPCCall} from './apitypes';
@@ -40,6 +39,7 @@ import * as fallbackRest from './fallbackRest';
 import {isNodeJS} from './featureDetection';
 import {generateServiceStub} from './fallbackServiceStub';
 import {StreamType} from '.';
+import * as objectHash from 'object-hash';
 
 export {FallbackServiceError};
 export {PathTemplate} from './pathTemplate';
@@ -135,7 +135,7 @@ export class GrpcClient {
   }
 
   loadProtoJSON(json: protobuf.INamespace, ignoreCache = false) {
-    const hash = objectHash(json).toString();
+    const hash = objectHash(JSON.stringify(json)).toString();
     const cached = GrpcClient.protoCache.get(hash);
     if (cached && !ignoreCache) {
       return cached;
diff --git a/src/grpc.ts b/src/grpc.ts
index 177781456..ac2f6469d 100644
--- a/src/grpc.ts
+++ b/src/grpc.ts
@@ -292,7 +292,7 @@ export class GrpcClient {
   }
 
   loadProtoJSON(json: protobuf.INamespace, ignoreCache = false) {
-    const hash = objectHash(json).toString();
+    const hash = objectHash(JSON.stringify(json)).toString();
     const cached = GrpcClient.protoCache.get(hash);
     if (cached && !ignoreCache) {
       return cached;
diff --git a/test/fixtures/google-gax-packaging-test-app/test/gapic-v1beta1.ts b/test/fixtures/google-gax-packaging-test-app/test/gapic-v1beta1.ts
index 01b52da86..9ce1307a0 100644
--- a/test/fixtures/google-gax-packaging-test-app/test/gapic-v1beta1.ts
+++ b/test/fixtures/google-gax-packaging-test-app/test/gapic-v1beta1.ts
@@ -357,7 +357,7 @@ describe('v1beta1.EchoClient', () => {
       );
     });
 
-    it.only('invokes echo with closed client', async () => {
+    it('invokes echo with closed client', async () => {
       const client = new echoModule.v1beta1.EchoClient({
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',