In the new image posted with the village behind it:
The "Minecart with Hopper" has cobble in it that is not transferring into the furnaces beneath it; because a regular Hopper is able to feed containers beneath it, this was an expected behavior.
Just checked, this bug still exists in Snapshot 13w03a
This bug still exists in Snapshot 13w03a
In the new image posted with the village behind it:
The "Minecart with Hopper" has cobble in it that is not transferring into the furnaces beneath it; because a regular Hopper is able to feed containers beneath it, this was an expected behavior.