This is an issue specific to Illia, and I was wondering if there is a fix for it. I've done extensive research and have found the problem multiple times, but no fix.
Illia is a mage that you can recruit as a follower after doing her quest. She is one of two female mages that specializes in both destruction and restoration (the reason I want her). The problem is that her default gear is a blue hooded robe. For some reason, this makes it so that she cannot wear chestpieces that you trade with her. If she equips a helmet, she will take off the robe (because it fills both slots), but she still won't be able to put any chestpiece on. This basically means that she's either stuck naked with a helmet, gloves, and boots; or a crappy blue robe.
Is there any fix for this? It seems like she's basically acting like the head and chest armor slots are permanently merged together.
I am using the AFT mod (Amazing Follower Tweaks). However, this bug is part of Illia, so I doubt AFT has anything to do with it. I am running on a PC.