I have had Butter since he was about 3 weeks old. He has a "dip" in his casque in the front, kind of like a dimple. About 3/4 the way up. He has had good supplementation, a varied diet, plenty of uvb. It isn't discolored, he is a veiled 6 months old. He has always had it, when he was little, it was less noticable, but now it is noticable.
I think it was always there.