Move Command on Chests/Dispensers causes the items to be removed

When using the move command on structures containing any containers (chest, dispenser etc.), all contents of these containers are removed, but only if the structure is being moved into the positive x or z direction, not in the negative.
This bug may be caused by an error in the code for the item ID storage of the movement of blocks used by the clone/move command, but unfortunately I could not find any reliable code that I could look at to confirm this.