Not entirely broken but whenever I temper an item it seems to store the recently used category of the item I tempered and because of this, any item that cannot use that temper is greyed out until I close out again.
For example, I enchanted my staff and the last temper was in the weapons category and the rest of my gear was greyed out. I did the same with an amulet in the resource category, everything else was greyed out except for rings.
It isn’t gamebreaking because I can close out of the npc and speak to them again but it’s a tad annoying!