iOS 13.6.1 Audio stops working during telephone call
My iPhone 6s and my girlfriend's iPhone 8 Plus, both suffer from audio loss during telephone calls. During a telephone call, audio will stop working (for 1 to 5 seconds, before coming back and then dropping out again at seemingly random intervals) and I cannot hear the person on the other side and they cannot hear me. This happened after updating to iOS 13.6.1, before the update, everything was working well on both phones.
Any suggestions and tips?
iPhone 6s, iOS 13