Strange microphone behavior on iOS in background

Hi, i am developing kind of voip app. I am using xcode 13.2.1 and testing on iOS 15. Communication is working over webrtc. When i try same app in browser and go to background everything is working ok and i can see orange status bar that some app is listening to microhpone. When i launch the same app using capacitor, everything is wokring ok until i send app to background. Then i can only hear incoming audio but i cannot see orange status bar and microphone is dead. And here comes the strage thing. While the app is in background and i launch some other app using audio and then quit this other app, i can hear the audio from my app in background BUT now also the mic is working with my app in background. But htere is still no status bar telling me that there is na app in background using mic. When i put my app in foreground and back in background then again the mic is dead.

I am using @mozartec/capacitor-microphone to request mic permissions on app start which works becasu mic works in foreground. In xcode i have added background modes capabilities for audio and voip.

What am i missing please?