Phone calls end themselves after ≈ 2 hours

I’ve had this issue for a while and never been able to think of why it’s happening.

While on the phone with several different people the call will end usually between 1h 50m and 2h with neither person manually ending the call. No power button is pressed and it happens roughly 1 out of 5 times. I have reviewed my settings and none of them make this issue.

Any more info needed please let me know