UPDATE:
Actually no update at all... still happening with version 1.3.00.30857.
Exactly what @PankajKumar-2452 said. Seems like Teams never releases the mic at the end of a call. So when I check the system for who is using the mic, it tells me it's Skype.
UPDATE:
Actually no update at all... still happening with version 1.3.00.30857.