Hi and welcome,
First thing I would try, is loading a skin that is all a solid color (basically a fully solid color image with no aircraft details). Try black, then red or blue. See if this same effect is happening on these solid color skins. Then you will have an idea whether it's some bug, or if there might be some mapping issue.
If this doesn't show up with a full solid color, then I'd use something like the panelfinder tool, and see what happens. You can get this tool here:
http://www.simmerspaintshop.com/foru...anelfinder-40/