ok, I have a very peculiar issue. My main display is a Dell 4K monitor (connected to a DisplayPort on NVidia 4090) and my secondary monitor is a Samsung tv (QN95A) connected to motherboard's HDMI and driven by the on chip INTEL gpu.
I have set Dell as primary and Samsung as secondary
When both displays are ON, everything is fine. If I actually DISCONNECT the Samsung from the HDMI cable, everything is fine as well.
BUT, when I have both of them plugged but the Samsung TV is switched off, the Dell monitor (main monitor) will randomly go into a brief video rescan, as if it is trying to reassess the screen borders. This looks like a zoom out - zoom in but it is not, the entire screen will momentarily shrink and then go back to normal. It may not do that for an hour and then it may do that every minute for some time, totally random behavior, with no correlation to what I am running (I may be running any desktop app or even doing nothing).
This error is non destructive ( computer does not freeze) but it is very annoying, especially when it it gets repeated frequently. It also seems to be a software error. It is happening over 3 years during which I changed from an AMD mobo cpu + NVidia 3070 setup to an INTEL mobo cpu + NVidia 4090 setup, and this error persists regardless of massive hardware changes.
The only way to stop it from happening is to actually unplug the TV HDMI cable from the computer (or to always have both displays turned on simultaneously). What is causing this behavior and is there a method to stop it from happening?