Bug still occurs on servers only
I updated Java to Java 7 patch 11 and redownloaded the snapshot (both client and server) and the bug still occurs. Updated LWJGL was because I thought the mouse issues (taking items out of crafting) with 13w01b were due to bad LWJGL
I was able to reproduce the bug 3 times
Chest after 2 pumpkins were added while I was uploading the first image
Chest before hopper adds another pumpkin
Redownloaded server jar and issue still occurs. I have a new crash report here