Additional meeting and call-related features and issues within Microsoft Teams for Education
I am having this same issue. The solution provided does not solves the issue. The gain slider still randomly moves from approximately 35 to 55 even without allowing applications to take exclusive control. This solution DID work momentarily. However, as soon as Teams was closed and reopened on the machine the problem returned and could no longer be solved by this fix suggestion.
This does not seem to happen on my Mac only on my PC. This seems to be a Microsoft bug. Is there an eta on a fix?