I've been gathering the various Dragon Priest masks and storing them on mannequins in the house. I decided it would be better to collect all the masks in one container so I took down the ones on the mannequins and put all of them in a table drawer along with the masks I was carrying. I left Lakeview Manor, but upon my return, the masks were on the mannequins *and* in the drawer. I now have two copies of a few masks. I haven't tried to duplicate this but FYI. Maybe you can sell them and keep them simultaneously. Anyone else noticed this (maybe with items other than just the masks)?