When u drop any item in the middle of two hoppers, it starts duplicating, here is an example duplication machine I made with a redstone clock and hoppers connected to dispensers.
As you can see the diamond starts trying to enter both hoppers, and starts duplicating.
MC-6006
Duplication machine with hopper.
Resolved
Duplicate
0
LuichoX
(Unassigned)
Unconfirmed
Snapshot 13w01b
Retrieved
Duplicate of: MC-5998 - Please use the search function to see if your bug has already been submitted.
Currently over 35% of tickets are being closed as duplicate.