Using hotkey cmd+q it gives prompt asking if I'm sure but clicking yes doesn't do anything else than close the prompt. Same behaviour as clicking no.

Are you sure about this? I’ve been using this all day. Maybe another app has hogged the commands somehow?

I've been testing this again today and can't replicate. I've never seen this before and nothing has ever changed with this hotkey function. Very strange.

Not able to replicate it anymore. Had only Mixo open when this was happening. cmd+q itself was working but the yes button after that didnt work.

Well right after I posted that I had it happen again. Was about to screenrecord but clicking the fullscreen button made Mixo close (or crash? not sure)

I would download and install the latest version from the website:
https://www.mixo.dj/download

This might re-establish the hot keys and permissions that might have got corrupted or something during an in-app update.

Worth a try!

Reinstalled now. Will update this when/if it happens again with hopefully a screen recording this time!