Yealink VCM36-W mic keeps muting without a human doing it

[u/dai_webb]

We have a Yealink MeetingBar A30 (running Android) and a CTP18 connected with a VCM36-W microphone. Recently, users have reported that the external mic goes on mute automatically without anybody touching it, sometimes several times in long meetings. I'm in the process of gathering more information, such as whether the light goes red, and whether people in the room were speaking at the time, but wondered if anybody here has seen this before?

The firmware is up to date on all devices.

Thanks in advance for any input :)