Droppers putting coal in Minecarts with Furnaces aren't powering the cart, it is just dropping the coal
Linked issues
is duplicated by 4
MC-258350
Hoppers cannot fill furnace minecarts with coal even though they can fill furnaces with coal
Resolved
MC-8417
Hoppers can't put Coal into Furnace Minecarts.
Resolved
MC-10996
Powered minecart doesn't take coal from hopper
Resolved
MC-62110
I can not load coal in a minecart with furnace with a Hopper
Resolved
This works as intended. Droppers are meant to:
a. drop items (which is what is happening)
b. put items into a CONTAINER (which a furnace minecart is NOT (unlike a chest or hopper minecart, it has no inventory or GUI)