@@ -287,8 +287,12 @@ class MethodChannelFirebaseFirestore extends FirebaseFirestorePlatform {
             null,
           );
 
-          // Allow the [runTransaction] method to listen to an error.
+          // Native may report an error while the result is being stored.
+          if (completer.isCompleted) {
+            return;
+          }
 
+          // Allow the [runTransaction] method to listen to an error.
           completer.completeError(error, stack);
 
           return;
 
@@ -0,0 +1,138 @@
+// Copyright 2017, the Chromium project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:async';
+
+import 'package:cloud_firestore_platform_interface/cloud_firestore_platform_interface.dart';
+import 'package:cloud_firestore_platform_interface/src/method_channel/method_channel_firestore.dart';
+import 'package:firebase_core/firebase_core.dart';
+import 'package:firebase_core_platform_interface/test.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mockito/mockito.dart';
+
+import 'pigeon/test_api.dart';
+
+class _MockFirebaseFirestoreHostApi extends Mock
+    implements TestFirebaseFirestoreHostApi {
+  final Completer<void> storeResultCalled = Completer<void>();
+  final Completer<void> releaseStoreResult = Completer<void>();
+
+  @override
+  Future<String> transactionCreate(
+    FirestorePigeonFirebaseApp app,
+    int timeout,
+    int maxAttempts,
+  ) async {
+    return 'transaction-id';
+  }
+
+  @override
+  Future<void> transactionStoreResult(
+    String transactionId,
+    InternalTransactionResult resultType,
+    List<InternalTransactionCommand?>? commands,
+  ) async {
+    storeResultCalled.complete();
+    await releaseStoreResult.future;
+  }
+}
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  setupFirebaseCoreMocks();
+
+  const transactionId = 'transaction-id';
+  const channelName =
+      'plugins.flutter.io/firebase_firestore/transaction/$transactionId';
+  const codec = StandardMethodCodec(PigeonCodec());
+
+  late TestDefaultBinaryMessenger messenger;
+  late _MockFirebaseFirestoreHostApi hostApi;
+  late Completer<void> eventChannelListened;
+  late FirebaseApp app;
+
+  setUpAll(() async {
+    app = await Firebase.initializeApp(
+      name: 'test-app',
+      options: const FirebaseOptions(
+        apiKey: 'api-key',
+        appId: 'app-id',
+        messagingSenderId: 'sender-id',
+        projectId: 'project-id',
+      ),
+    );
+  });
+
+  setUp(() {
+    messenger =
+        TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger;
+    hostApi = _MockFirebaseFirestoreHostApi();
+    eventChannelListened = Completer<void>();
+
+    TestFirebaseFirestoreHostApi.setUp(hostApi);
+    messenger.setMockMessageHandler(channelName, (ByteData? message) async {
+      if (!eventChannelListened.isCompleted) {
+        eventChannelListened.complete();
+      }
+      return codec.encodeSuccessEnvelope(null);
+    });
+  });
+
+  tearDown(() {
+    TestFirebaseFirestoreHostApi.setUp(null);
+    messenger.setMockMessageHandler(channelName, null);
+  });
+
+  test(
+    'does not complete the transaction future twice when native reports an '
+    'error while storing a failure',
+    () async {
+      final firestore = MethodChannelFirebaseFirestore(
+        app: app,
+        databaseId: '(default)',
+      );
+
+      final transactionFuture = firestore.runTransaction<void>(
+        (_) => throw StateError('handler failed'),
+      );
+
+      await eventChannelListened.future;
+      unawaited(
+        messenger.handlePlatformMessage(
+          channelName,
+          codec.encodeSuccessEnvelope(<String, Object?>{
+            'appName': 'test-app',
+          }),
+          (_) {},
+        ),
+      );
+      await hostApi.storeResultCalled.future;
+
+      unawaited(
+        messenger.handlePlatformMessage(
+          channelName,
+          codec.encodeSuccessEnvelope(<String, Object?>{
+            'error': <String, Object?>{
+              'code': 'deadline-exceeded',
+              'message': 'Transaction timed out',
+            },
+          }),
+          (_) {},
+        ),
+      );
+
+      await expectLater(
+        transactionFuture,
+        throwsA(
+          isA<FirebaseException>()
+              .having((error) => error.code, 'code', 'deadline-exceeded'),
+        ),
+      );
+
+      hostApi.releaseStoreResult.complete();
+      await Future<void>.delayed(Duration.zero);
+    },
+  );
+}