Additional settings-related features and issues within Microsoft Teams for business
Yep, (1) is exactly as you describe already.
Anв still, (2) is exactly where the issue presents itself: when I join an MS teams meeting, all other apps that produce sounds at the moment gets muted in the volume mixer, and I have to un-mute them manually.
I've tried all the MS teams options related to sound devices, volume, etc. The issue happens regardless of anything I change there.