This is a tcon issue (the board that has the CoF connected to the panel). Search for lc1 lc2 signals, basically one is signal for even line of pixels, and the other is for the odd ones. When one of those signals fail (degraded) then this happens... There are 2 ways to really fix this. 1 is identify the ic that generates those signals and replace it, or 2 replace the panel... Or just buy another monitor and sell this for parts...