External screen regularly flashes off unless microphone is active

I’m running Ubuntu Budgie on an Asus GL552VW laptop.
I updated to the newest version of the OS a few days ago after a prompt and since then have noted the external monitor connected using HDMI) is repeatedly flashing to black for anywhere from 0.2 to 5 seconds at a time, with gaps ranging from 1 second to 1 minute.

Bizarrely, the only way I have managed to stop the issue is to leave the sound options open in the settings, as that switches the microphone on. I’ve also tried recording in audacity while settings are closed, which also works.

Does anybody here have any clue as to what could explain this behaviour and how I might go about fixing it?

Many thanks!

Suggest try a different HDMI cable. It could be software change that may be more sensitive to a hardware fault.

If that doesnt work then please report an issue to launchpad so that Canonical are made aware

ubuntu-bug linux

As a workaround, your 21.10 kernel should still be available hopefully. When booting press and hold the shift button to display your grub. Choose the advanced option and choose the 5.11 kernel