Top of maximized windows stops responding and becomes invisible or black

[z0 l1]

Problem in details:
I have a 2 monitor setup and recently on my main monitor sometimes when the window is maximized the top of the window (around 100 pixels) stops responding. It's not my monitor because when I set the other monitor to be the main monitor the problem just disappeared, and setting it back didn't bring the problem back.

Occurences:
In-game: (only had it in COD Warzone so far) it's a black bar.
Chrome: the top part becomes white, full screening (F11) makes it good.
Steam: the top part becomes a void(?) it's like not there.

This demonstrates the "void effect" the best:

^
On the picture I right clicked on the top and its like I right clicked on windows desktop even tho there is a white border around the missing part.
It happens a couple times a day for a few days now.
I'm completely clueless and I haven't found any problem like it (or just could not find the correct name for it). help

 

[Cycloid Torus]

Don't know for certain, but my guess is different native resolutions - sometimes both are set by the lesser resolution - leaving blank at top of higher resolution monitor.

I use two monitors and had this issue on occasion, so I moved the lesser resolution monitor to my spouse's system and bought a duplicate monitor (used) from eBay.

 

[z0 l1]

Don't know for certain, but my guess is different native resolutions - sometimes both are set by the lesser resolution - leaving blank at top of higher resolution monitor.

I use two monitors and had this issue on occasion, so I moved the lesser resolution monitor to my spouse's system and bought a duplicate monitor (used) from eBay.

Forgot to include that the monitors are the same resolution :/ Thanks for answering

 

[Cycloid Torus]

If not hardware, then software. What software might be working on the display or freely adjusting screen? What might you have actively defining the screen boundaries? Any utility installed in the last few days?

You said, "when I set the other monitor to be the main monitor the problem just disappeared, and setting it back didn't bring the problem back" which makes me think there is an app which does not play well with Windows 10 and requires a forced reset to be re-instructed in the 'rules'.