Oh, I get the same problem so all my ocs are hat less. . .
I think it was something around 22 and 24 in the hats, that is the problem, so if you use the arrows and scroll round, you can get to all the other hats, and if you scroll to the last page through the arrows, you can actually click on it and it will open the whole thing to show you all the hats on the last page as long as you do not go near page two you can give your characters hat, 😁