Spawners with minecarts with blocks that have offsets

In 13w37b, this was not an issue. However in 13w38a, it is:
If there is a spawner that spawns minecarts with custom display blocks in them, the block doesn't show up in the spawner. The image attatched says it all... I really don't know if this was intended or not, but whatever it was PLEASE change it back!!! A whole map is pretty much broken because of it.