At first, I was skeptical with arcadia lights from LYR but after changing to it, I really like the arcadias. When you buying a fixture, make sure it has a reflector. Get the T5s they are much better.
He might be molding and getting ready to shed. Most of my chams turn darker like that before they shed. I would freak out and the next day a full shed. How long have this been going for?