If you have a fair amount of server lag:
Put an item or stack of items from your hotbar into your inventory.
Quickly open a chest.
The items can duplicate under these conditions, with the stack in your hotbar reappearing.
Linked issues
Comments 5
Can you provide a video of this happening on an unmodified 15w42a server, showing the items being duplicated and then dropping both the original and the duplicated set of items on the ground?
Sorry, but
I've had reports of it happening in survival
is not believable enough. If this does happen to you personally, please do create a new ticket with all relevant information.
It's not just creative mode; I've seen MC-5415 happen as well. This is across gamemodes. I've personally experienced it in creative mode, and I've had reports of it happening in survival. Furthermore, I had no trouble with this before 15w42a. Thus, this is a new bug and should be treated accordingly.