Hoppers pointing at minecarts with chest sideways may fail to fill the cart

Hoppers pointing at minecarts with chest sideways fail to fill the carts depending on the direction.

Steps to reproduce:

1. Place a minecart with chest on a rail
2. Place a hopper pointing at the cart sideways.
3. Put some items into the hopper.
   

What happened:
The hopper doesn't transfer items into the minecart with chest depending on the direction. In my screenshot, the upper two work as expected but the lower two don't.

What I expected:
Hoppers fill the carts regardless of direction.