Ok so this glitch is very odd and a little hard to explain..

I have the house in Markarth with all the furnishings. Everything works fine, even the mannequin.

I'll put my weapons on the racks in the war room, save, turn off my xbox, load the save game again, and everything is fine. But if I put any armor on the mannequin, save, turn off my xbox, then back on and load the save, all of my houses furnishings disappear, except the mannequin, which is now in the middle of the room.

This only happens if I turn the xbox off. If I load the save after saving, this does not happen. But when I turn it off and on, then load, everything is gone.

And my artifact weapons that I had on my racks? Completely gone, just disappeared, bc the racks are gone too.

I have reproduced this incident 3 times in a row. Luckily I had the autosave from when I entered the house so I didn't lose my artifacts.