This issue is usually monitor specific. Try unlocking the taskbar and see if it goes away..
Also, make sure the device drivers for your graphics card (if you have one) or on-board graphics (e.g., AMD Radeon R7) are up to date if unlocking the taskbar doesn't fix it.
This does appear to be a screen painting issue.
Are the monitors the same? Does your system have on board graphics?
If this didn't happen before, what did you change that resulted in this happening?Graphics card drivers are up to date. I have two monitors and using an RX 550 if that helps anything. But this never happened before
What motherboard do you have?
If this didn't happen before, what did you change that resulted in this happening?
After trying one monitor advise of the result.