Item Duplication Bug

[cttw]

My character has duplicated 2 items. First it was the Tooth of the Mouth, of which I suddenly realised I had 2. I transmo one and kept playing. Then it was a simple low level wizard hat that got duplicated. I think I have some ideas about the mechanics of the bug. It seems to happen when I change level and get the transmo chest list. If at that time I drag straight from that list into an occupied inventory slot, then I will have 2 of the item I was already wearing, and the new item from transmo list will be lost.

I've played a lot with other classes before without this bug, but with this skeleton marauder I got it twice already at lvl 9.

I can send you the save if needed, but it's too big to attach here in the forum.