• note, original world was created in Snapshot 18w49a

After traveling to my Map room. I see that the Item frames, and the maps inside
are invisible and unable to be selected, with the pick block function, in Creative Mode.
On Reloading the world ... the Item frames and Maps are partially visible, but the
villagers are not (can still hear them though) . When the world loads in fully The Item frames
and their objects inside pop off the wall. Soon after, the villagers "load" in. 

*Edit Items have not duplicated for me..
Result below is the same when I delete this world and reload from a backup save.