[AC Question]

This happens at random. I've noticed it about 5-6 times now. After about 15-20 mins into the conversation, I can't hear people on the call, but they can hear me. I've updated the software, reset the phone to factory settings, and restarted. Problem still continues. It's dosen't happen all the time, just random.
Anyone else? Any suggestions?

[B. Diddy]

Welcome to Android Central! Try booting into Safe Mode, which temporarily disables all 3rd party apps. https://support.t-mobile.com/docs/DOC-25053

If the problem disappears in Safe Mode, then something you installed is causing the problem. You may have to uninstall apps one by one until the problem disappears. If the problem persists in Safe Mode, then it's more likely to be a hardware or firmware problem.