I went onto my creative world for playing with snapshot things, excited for the new shapshot.

To my surprise, all my signs, item frames, chests, and custom heads were gone! They weren't were they should be. I found one item frame left, but that was all.

Steps to Reproduce:
1. It might not work for every world, but copy a save folder you know has lots of these items (Signs, Item frames, Chests, Heads, Possibly paintings)
2. Open up the copy, and you will most likely find them missing!

The Console says:
Client> 2013-09-20 16:44:09 [CLIENT] [SEVERE] ########## GL ERROR ##########
Client> 2013-09-20 16:44:09 [CLIENT] [SEVERE] @ Post render
Client> 2013-09-20 16:44:09 [CLIENT] [SEVERE] 1282: Invalid operation
Then it repeats the one below about a thousand times
Client> 2013-09-20 16:44:09 [CLIENT] [SEVERE] ########## GL ERROR ##########
Client> 2013-09-20 16:44:09 [CLIENT] [SEVERE] @ Post render
Client> 2013-09-20 16:44:09 [CLIENT] [SEVERE] 1283: Stack overflow