This happens when you are in a Teams meeting and you have to use Quick Assist to connect to the client.
Best / Recommended Fix
Mute Quick Assist audio on your PC
Quick Assist itself doesn’t have a “mute” button, but Windows lets you mute it per app.
- Right‑click the speaker icon in the system tray
- Click Open Volume mixer
- Look for Quick Assist (or sometimes Remote Desktop / System Sounds)
- Mute it or drag its volume to 0
Teams audio will continue normally
Echo stops immediately