The bug
Closing your inventory while you are holding an item with your cursor does not drop it properly. Neither stat.drop is increased nor you are set as Thrower of the item.
Steps to reproduce
Create a
stat.dropscoreboard objective and show it on the sidebar/scoreboard objectives add droppedItem stat.drop /scoreboard objectives setdisplay sidebar droppedItemPut an item in your inventory
Switch to Survival or Adventure mode
/gamemode survivalOpen your inventory and pick up an item with your cursor
Close your inventory
→ The item is dropped but yourdroppedItemscore does not increase
Confirmed for 1.9