I had fully upgraded mage set. Now I don't have any item from this set. Are you going to fix any bug from hundreds here? =/
does the item is equipped on heroes? or its in your bag?maybe you accidently bulk grind or sell it without you notice.just maybe thought, since i never lose any item.
Probably items were put on some hero - who knows. It's normal when the game warns you or forbids to dismantle such hero in this case. But not this game...
Hmm.. did you transcend the heroes using that gear? You will lost the gear and devil gem if that happened.