... a screen capture only captures the signal sent to the screen, not what the monitor is actually showing, which you managed to capture by a camera instead. This means the video feed was OK, or it would be both on the screen capture and monitor image. This means the problem IS with the monitor. Too high a refresh rate might cause that corrupted image to happen on monitor, but more usual is the monitor will either not display anything other than an "out of range" notice when such is the case, or will show a compressed image, smaller than full screen size. So, I also don't think it's due to high refresh rate. I've seen similar on older analog CRT type monitors and it was related to failed capacitors. I think you need a new monitor.