Screen bugging out (GPU or monitor fault?)

Hey guys. I have built my PC half year ago and havent had any problems since few weeks ago. I have noticed that sometimes when I turn ON my pc, the screen bugs out and is unable to fix itself unless I unplug the HDMI cable and plug it back into GPU multiple times till it finally fixes itself. After i run my pc this problem does not occur but if I turn it OFF and back ON again there is a chance that my screen will freeze again. I am very confused as I have never heard anything simillar before. Uploading a picture of my bugged monitor as well.
Could it be my monitors fault or gpu??

https://imgur.com/a/dtRIwGu

Easiest way to rule out the monitor is to try the system with another monitor (or any modern TV with an HDMI input. If it doesn't happen, it's quite possibly an issue with the monitor.

If it does happen, it doesn't necessarily mean the GPU has a hardware fault, but does suggest an issue of some kind with the PC.

If you test a different monitor and it also shows the same issue, you can try sweeping the drivers with DDU and performing a clean install of the latest drivers downloaded directly from the Nvidia/AMD website
http://www.guru3d.com/files-details/display-driver-uninstaller-download.html
If that fails, do the same again with DDU and try some older drivers

If that fails, you can try a different output on the GPU. e.g. if you use HDMI normally, see if it also happens with DVI

You can also try a different HDMI cable to rule that out.