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.
Environment
Hopper with water stream above it holding an item.
MC-6310
Hopper duplication bug
Resolved
Duplicate
0
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.