Scaling/Color Issues in Mesen(NES)?

Just look at the left bottom of my screen. I wonder why is there such a diagonal color difference? I also noticed this in other NES games and it is more noticable when moving since the line basically will move on place. I guess it is somehwat of a scaling issue? However i didn’t notice this on my other NV System. So it seems to be an AMD thing. Though there it seems to happen on Linux and Windows. ANyone has a clue how to fix it?

Can you focus on what’s wrong, because I don’t see anything.