The global volume automatically increasing to 20 is now fixed. If you are changing the Teams app volume you may still have an issue.
Thanks for your feedback. Please let us know if you are still having issues.
An error occurred while saving the commentKen H commented
Still broken. Join a call and volume goes to 100% every time. Set volume to 50% as I'd like and it's fine. Get another call thirty seconds later and Teams forcefully sets my headset volume back to 100% so I have to adjust the volume back to 50% again.
This is absurd.