Battery Drain when phone call is accepted during another app open

Hey there,

I hope I can explain what I expirienced now twice as it is a bit hard to explain.

So basically I was on my phone (iphone 12 mini) either browsing in safari and the second time it was the facebook app or whatsapp and I received a phone call with the small banner on top. I accepted the call using the small banner on top and I did not swipe away the app I was using before.

During the following phone call I noticed the phone getting hotter than usual and after the call the battery had dropped an unusual amount. So I checked the battery status and it showed my, that actually the app I had open, while I accepted the phone call was using most of the battery power, which is totally surprising me. It seems to me, if that app is left open during receiving a phone call, it gets stuck somehow propably trying to connect to the internet or doing god knows what.

I do have a dual sim configuration and both times did happen, I received a call on the line, which I do not use by standard for mobile connection, but I was in Wifi connection anyway.

I did a couple of tests and it does not seem to happen, when I receive a phone call and accept it when either the phone is locked or of there is no other app in the foreground.

I must say, I have also background app refresh disabled and I'm wondering if I can propably prevent it by showing incoming calls in full screen instead of the banner....

Did anybody here have any similar expirience?

Thanks a lot in advance......