I was viewing all of the custom wearables in the chest layer in the beta wardrobe and suddenly received the Off Your Chest achievement. When I then viewed all the custom wearables on the head layer the same thing happened again but for the On Your Head achievement. According to the counter for that achievement, I have more than 800 items in my wardrobe that go on the head layer. I definitely do not. I don't know if this has happened to anyone else. Didn't find anything on the forums.

Yes, several weeks ago. I had forgotten I had a thread about it.