Hi Master,
Hope all is well, let's try to find the root cause of this issue, although it could be software related, it sounds more likely to be hardware corruption.
1) What brand/model is your monitor?
2) What image data cable are you using? HDMI? Usb-C? Have you tried swapping out the cable?
3) Are you using a hub/docking station? If so does the issue persists with a direct connection?
4) Have you been able to replicate the issue on a different machine?
5) Have you tried to use that same cable on a different monitor to see if the issue persists?
We can try some troubleshooting depending on the answers here!