Car Play not using car speaker for calls

2018 Audi A4 - everything was working fine. I think the problem started with iOS 15.4.1. Now when placing or receiving a call, car play recognizes the phone is in use, but all sound is only on the phone - cannot play through the car speakers. Is this a known bug in the new software? Tried resetting the car and the phone - tried another updated phone with the same issue.