DivX 5.0.2 had problems with GMC, yes. As for DivX 5.0.3, well I don't know. They screwed up B-frames in this release, so I'm staying away from it (artifacts all over my encodes). I would assume they didn't fix it, as they state directly it isn't compliant with the standard for MPEG4/GMC (thus, it's not in any of their little 'profiles').