I actually prefer it this way...
No not a broken resource pack, no... I found out what it is, when you have an item in your inventory then it will appear. but if you have 2 or more of that item in your inventory (same stack) it will be fixed...
this is an issue that i encountered on my adventure map... its not that there going slow... its that the game ticks are lagging...
its the game ticks lagging... im not sure why this happens, i had to restart my adventure map because of it!
i didnt kow about that feature... THATS AWESOME!
oh, ok thanks, i guess its because im using a 1.7 resource pack on the snapshot, ok bye!
i think this is supposed to happen