Application Integration always acknowledge message sent by Pub/Sub push subscription

[EdRamos]

Hi, everyone

A Pub/Sub push subscription's endpoint is an application integration. The subscription has been set up with a retry mechanism and a DLQ topic.

The happy path works as intended.

But in all the following scenarios, Application Integration acknowledges the message and returns OK, thus defeating the purpose of the retry mechanism and the DLQ topic:

• When the application integration does not exist
• When the application integration is unpublished
• When the application integration fails

I opened a ticket with Cloud Support and Application Integration behavior has been confirmed. Everything in the Pub/Sub objects definition is fine because we implemented a similar solution replacing the application integration with an Apigee X proxy and all works as intended.

Any thoughts on why Application Integration acknowledges the messages in the scenarios bullet-listed above?  It is really baffling to me.

Thank you