I have a similar tv (LG B7) and believe I’m experiencing similar issues with my PS2 in 480p mode (SoG, RGB SCART). It looks like some sort of edge enhancement or haloing effect, but slightly blurred. It’s like there’re two layers, a full colored layer and a transparent which are not completely alligned. It’s not as visible with component cables, probably because component is less sharp.
I haven’t done any testing with my Xbox, but will try a few games tonight and report back my findings.