While listening to podcasts or watching videos, my bluetooth headset has good quality audio. However when I receive a phone call, the phone call audio crackles and breaks up. It is audible, but the same way a very bad quality phone call from across the globe is still audible. The audio of the call is in actuality just fine and the crackling etc. appears somewhere between the phone and the headset, since if i drop the bluetooth connection and continue on speaker or normally, phone-on-ear, there are no issues at all.
The issue happens during ordinary phone calls and whatsapp phone calls, but not during discord chats.
My headphones are sony WI-C400. I’ve used these on a number of different phones and the issue is only on my fairphone 3. I also have a 2nd pair of said headphones and the issue repeats identically with them.