I did some searching but I couldn't find anything posted about this. This is one of those, I'm sure I'm the last to notice but...
I took these screenshots from a few versions of ESB. In each one, in this scene, Fett has partly grey looking knees and in all but the fan color adjusted version grey shoulders too.
ADYWAN color adjusted version:
HD Version (Pre-Blu-Ray):
Film color issues? In every other scene it looks fine just this one shot.