This works in singleplayer and multiplayer, and is not a graphical glitch. This glitch affects the security of almost any minecraft server becuase any player can take the items from any chests without opening or breaking the chest. The player does not even need building permissions.
How to reproduce:

1) Place down a chest and put an item inside of it
2) Have a head in your hand
3) Hold the head in your hand and then place the head on the visible block below a chest from above (becuase chests are one pixel smaller than other blocks)

In other words, right click/place the head under the chest by looking at the block below the chest, since chests expose the blocks below them due to how they are 1 pixel smaller than normal blocks. Even if the player does not have permissions to place the head, the chest will still break and the items will come out.