App switches spuriously to speakerphone and back while in call despite proximity sensor being disabled

[swedneck]

trafficstars

Using version 5.11.3 from f-droid

[tswistak]

I also have proximity sensor disabled and haven't encountered anything like this. Just to be sure - are you locking your phone screen after answering the call and then move it to your ear? Because it sounds like your ear/cheek is clicking a button on an unlocked screen (and it doesn't lock automatically due to disabled sensor).

[swedneck]

That was my first thought as well, but this happens even with the phone held in front of me.