Environment
If a dropper tries to move items into a container that can only hold certain types of items(Like a Furnace, Brewing Stand or Beacon) that don't normally fit(Like a stack of dirt in to a beacon) then the item stack will get removed and only 1 of the items will be left.
To recreate:
1)Place a dropper facing in to a beacon
2)Put a stack of 64 dirt in to the dropper
3)Power the dropper
4)See that the stack disappears and only 1 block of dirt is left
Duplicate of MC-7654, please use the search function to see if your bug has already been submitted. Currently over 51% of tickets are being closed as duplicate.