Phone call interruption on Android

Using 2.02.04 on Unity 2020.3.25f1

Our app normally handles pause resume on Android OS, app mutes on pause and resumes on … well resume.
When a regular phone call is received (ringing) app mutes, which is ok I guess, but once user answers the call, the app sound is restored and being heard with overlapping phone call. Other call capable apps (like viber, whatsapp, slack) work a bit differently, during “ringing” ring audio overlaps with app audio, but once answered, our app is properly muted and later restored when call is ended.

Is this something I “accidentally” broke or?

I have not been able to reproduce this issue. In the latest version of FMOD there should be no need to manually handle mixer suspsend and resume. Would it be possible for you to update to the latest version of FMOD, remove your mixer suspend/resume calls and see if that has a better result?