diff --git a/src/invocation/InvocationService.ts b/src/invocation/InvocationService.ts
index e03ca58e5..b3ac72ab9 100644
--- a/src/invocation/InvocationService.ts
+++ b/src/invocation/InvocationService.ts
@@ -291,8 +291,8 @@ export class InvocationService {
         if (this.backupAckToClientEnabled) {
             const listenerService = this.client.getListenerService();
             listenerService.registerListener(backupListenerCodec, this.backupEventHandler.bind(this));
-            this.cleanResourcesTask = this.scheduleCleanResourcesTask(this.cleanResourcesMillis);
         }
+        this.cleanResourcesTask = this.scheduleCleanResourcesTask(this.cleanResourcesMillis);
     }
 
     private scheduleCleanResourcesTask(periodMillis: number): Task {
@@ -306,7 +306,9 @@ export class InvocationService {
                     this.notifyError(invocation, new TargetDisconnectedError(connection.getClosedReason()));
                     continue;
                 }
-                invocation.detectAndHandleBackupTimeout(this.operationBackupTimeoutMillis);
+                if (this.backupAckToClientEnabled) {
+                    invocation.detectAndHandleBackupTimeout(this.operationBackupTimeoutMillis);
+                }
             }
         }, periodMillis, periodMillis);
     }
@@ -316,7 +318,7 @@ export class InvocationService {
             return;
         }
         this.isShutdown = true;
-        if (this.cleanResourcesTask != null) {
+        if (this.cleanResourcesTask !== undefined) {
             cancelRepetitionTask(this.cleanResourcesTask);
         }
         for (const invocation of this.pending.values()) {
diff --git a/test/invocation/InvocationServiceTest.js b/test/invocation/InvocationServiceTest.js
index 5b442129b..fda190227 100644
--- a/test/invocation/InvocationServiceTest.js
+++ b/test/invocation/InvocationServiceTest.js
@@ -92,7 +92,7 @@ describe('InvocationServiceTest', function () {
         expect(client.getListenerService().registerListener.calledOnce).to.be.true;
     });
 
-    it('should not start clean resource task and register listener when client is unisocket', function () {
+    it('should start clean resource task without listener registration when client is unisocket', function () {
         const config = new ClientConfigImpl();
         config.network.smartRouting = false;
         const client = mockClient(config);
@@ -100,11 +100,11 @@ describe('InvocationServiceTest', function () {
         service = new InvocationService(client);
         service.start();
 
-        expect(service.cleanResourcesTask).to.be.undefined;
+        expect(service.cleanResourcesTask).to.be.not.undefined;
         expect(client.getListenerService().registerListener.notCalled).to.be.true;
     });
 
-    it('should not start clean resource task and register listener when acks are disabled', function () {
+    it('should start clean resource task without listener registration when acks are disabled', function () {
         const config = new ClientConfigImpl();
         config.backupAckToClientEnabled = false;
         const client = mockClient(config);
@@ -112,7 +112,7 @@ describe('InvocationServiceTest', function () {
         service = new InvocationService(client);
         service.start();
 
-        expect(service.cleanResourcesTask).to.be.undefined;
+        expect(service.cleanResourcesTask).to.be.not.undefined;
         expect(client.getListenerService().registerListener.notCalled).to.be.true;
     });