Problem is drivers. The PinePhone itself is based on quite old hardware, and lacking of drivers. And nobody wants to write drivers for old hardware. The issue was resolved with former Android based phones by using the already available drivers.

PinePhone Pro is using much newer hardware so there may be hope for it.

I got my PinePhone a long while ago with the Community versions. I was really turned off by Manjaro Phosh so I flashed an SD card with Ubuntu Touch and been quite happy with it.
Even calls were working great. However, I really never talk on it, and have not made or received a call on it in nearly two years. I also do updates on it often.

Today is the first time in a long time I got a call on it, and there was no audio.

Thinking it was due to the to sleep mode/standby mode, I rebooted the phone and then made some test calls. Still no audio.

Anyone know what happened?

You should also consider looking at the Pine64 forum. Seems a lot of people are not happy with it. After reading all the comments, I will be doing a hard pass on it.