I am also exercising one interesting moment - this thing has happened 2-3 times already. But never in the morning - always in the evening.
I have 3 pc’s connected to my monitor - my home pc(dp), my working pc(hdmi), and the lab one(also hdmi). And evening is the moment when I suspend my working pc (Ubuntu), switch to my main(win10). And, later, I turn it off and move to the tv. And this is the time period, where I usually find that the light controls are unresponsive (controller fails to capture messages).
Although today it was strange, and I first noticed that the few clicks were processed with a delay. After it was zero responsivness. But all returned to normal once I switched the monitor input to the lab pc (and the kb and mouse to bt… and made a mouse movement).
Have a hunch there is some suspend/sleep trigger happening by the monitor going to sleep related event(I’ve seen google bring up this topic a few times).