I completed all of the quests for the Daedric artifacts and stored them in a cabinet in Hjerim, the house that you can buy in Windhelm. Once I had all of the Daedric artifacts I stopped playing the game for while, because the Oblivion Walker achievement was all I needed to complete the game (not including the DLC achievements). However, I recently started playing the game again after downloading the Dawnguard, Hearthfire, and Dragonborn add-ons. When I went to use one of my Daedric artifacts, the entire cabinet was gone. I am not talking about the contents of the cabinet, I am talking about the cabinet itself. There was a bookshelf where it used to be. I don't think it had anything to do with child adoption, because it was on the second floor of the house and the child's room is on the first floor.

What happened? Was there some sort of update to Hjerim? Is there any way to get my things back?