OK so it only happens when I am on the USB connection when using a MS Teams meeting. Cabled is fine. Webex and Zoom is fine.

Yes and I’ve worked out it’s when I’m on a Microsoft Teams call over the USB dongle. Doesn’t beep When wired?

When the cable is plugged in- perfect. Running from the USB dongle is very bad.

And it's only during MS Teams calls. Webex direct is fine.

In fact - it seems to be when I'm speaking that it triggers - perhaps there's a audio limit triggering? Very frustrating and distracting!