We have an auto-pause feature where agents are paused after a call, and manually un-pause when they’re finished with wrap-up. This worked perfectly in Asterisk 11.

We’ve recently switched to Asterisk 16, and we now occasionally hear reports of users saying a call rang-through after the auto-pause.  The initial thought that this happened during the brief time the call ended, and the time the pause was activated. So we added a custom state to the device that answered the call set to INUSE as soon as the call was answered.  Once the call was completed, the agent gets paused, and only then does the state get set to UNAVAILABLE.  Hints are set appropriately for the user. Testing manually by setting this custom state stops queue calls from getting to the user.

We still occasionally get ring troughs though.  It happens somewhat rarely, and likely works fine 99% of the time.

We’ve tried testing this using sipp to create a lot of queue calls. 
Even with a high load of around 40 calls distributed on 2 queues we haven’t been able to reproduce the behavior.  We’ve tried answering more than 70 calls in a test environment, and none have reproduced the ring-through behavior.

Has anyone seen any similar behavior in queues in Asterisk 16 where a call goes to an agent even though they’re paused/INUSE? Any other suggestions are appreciated, though gathering more data is especially difficult since the event seems to be rare.