Hopper doesn't suck items everytime, they create an infinite amount of that item inside but don't delete the dropped item. You have to pick it up if you want to stop duplicating it.
MC-6310
Hopper duplication bug
Resolved
Duplicate
0
Bartholomew S.
(Unassigned)
Unconfirmed
duplication
Snapshot 13w01b
Retrieved
62nd duplicate of MC-5998, please use the search function to see if your bug has already been submitted. Currently over 40% of tickets are being closed as duplicate.