Teams seems to work normally in a container for me but I realized even though I have it open all day... I just use chat, not video/audio calls. I tried to call someone yesterday and it turned out Microsoft says they don't support FF and I have to use Edge or Chrome (or the app, preferably, of course). This is not a problem with the container itself, though.

Interestingly enough, when I asked my colleague call me, they didn't receive any feedback message - it was as if I was not responding to their call. Another lame thing on the part of MS as it could introduce (potentially never verbalized) problems into communication.

With containers, subdomains and redirects I’ve found switching off network and forcing each subdomain to open in a particular container 1-by-1 to work well.