Ive seen my cham eat a bit of her shed not everything, my geckos however eat everything haha no cleanup I think it may be a way to get back some calcium or something, I kind of vaguely remember reading that somewhere, probably in other posts, but not 100%
My previous veiled I had ate his shed all the time. It's good calcium. It's normal. I haven't seen a whole lot of chameleons do it but I know lots of other reptiles do it! Maybe he thinks he's a gecko!