At random times while mining an area out, items in the hotbar start to be thrown. I've noticed that behind the items icon a green bar will slowly fill and the item will then be thrown. Then the next slot in the hotbar will do the same until everything is emptied. I can go pick the items back up and it will continue to throw the items back out just as it did before. The only way so far that I can get it to stop is to save and quit, then go back to the home screen and completely close minecraft out, then reopen the game. Saving and quitting, then just reloading the world will not fix the problem, the game has to be completely closed out. Also, so far it only seems to happen in survival mode. I'll update when it happens again and see if I'm able to reproduce it. For now it seems to be random and annoying.