Before getting the robes I read that I would be able to wear circlets. At least in my game, that's wrong, but I can't find any evidence for this online. What could be the issue?
Welcome to the forums. I have used the archmages robe with a circlet but not since the last patch. What version are you using? Are you on PC using the unofficial patch?
Hmm... I just loaded up a game and tried it. It still works for me. I tried a few combos like a with a regular hat, the circlet removed it but with the archmage robes it did not. This must be some mod conflict.