If you block the two input slots in a Furnace and connect a Hopper with iron ingots in, the iron ingots are put into the output slot and on removal, you still get XP for it, generating free xp.
Linked issues
duplicates 1
Comments 4
Duplicate of: MC-5748 - Please use the search function to see if your bug has already been submitted.
Currently over 35% of tickets are being closed as duplicate.
Confirmed.