WE had a lot of chests labeled with item frames. All of a sudden, All our item frames vanished.

Hello! 

In my realm We have a house with about 50 chests that were all labeled with Item frames. It's been fine. I logged in today and all the items in the chests were there, Though All the item frames that were labelling the chests are gone.  No reason. all 50 of them, just gone. Everything else is normal.