Thanks for feedback! We have fixed many Bluetooth issues in recent updates, so we recommend taking the following steps:
(1) update to the latest Teams app,
(2) clear Bluetooth cache if you are using Android (search on Bing for how to do this for your particular device)
(3) pair your Bluetooth headset again.
If you are still experiencing issues, please help us by posting your phone model, BT headset model, current Teams client info, and when the issue occurs. You can also send us more information by choosing “Report an Issue” from Settings in the Teams app. Thank you!