Put the summary of the bug you're having here

What I expected to happen was...:
Nothing to happen

What actually happened was...:
When i logged out and in, in my single player map the item in the item frame, and the item frame duplicates to around 4 stacks

Steps to Reproduce:
1. Find a chunk border south.
2. Make a 2 block high tower (any block).
3. Inside the chunk behind the 2 block tower set 1 block.
4. On that block you set a comparator to point north.
5. Set a item frame 2 blocks south of the comparator.
6. Put you preffered item in the item frame.
7. Stand inside the chunk.
8. Log out and in.
9. Wupti a little lag and the items appear.