Found a weird glitch.

So, after returning from a quest to the tundra homestead where i had some armor displayed. nothing strange thus far. But the armor was unequipped on the mannekins, but they were still there, so i grabbed some things. then, later, the armor reappeared on the mannekins. And that means that now I have miraak's mask twice. No clue why this happens, but not the first time those mannekins created duplication items.