I do notice an "auto-play" that starts before/after/during making calls. Sometimes I can open the volume panel and see that there is a sound playing in Teams and can press the pause button to stop it.
Sometimes when I answer a call a paused YouTube video in Chrome will suddenly start playing.
Similarly, videos start playing in Chrome when I answer a Discord call.
Sometimes a paused Plex video will suddenly resume for no apparent reason.
Maybe this issue has less to do with Teams specifically as it does a general "pause and resume playing my video/audio when getting a call". Is there some feature in the OS that attempts to pause and resume playing something queued? Maybe when the Bluetooth profile switches from rich audio to voice?