Spawners with minecarts with blocks that have offsets

In 1.7 this was not an issue, but for 1.8 it is. For a full description, go here: MC-31760

There is a world i attached there, and screenshots, and an explanation.

At the end of the description, i stated that it broke an entire map. Well, it's done it again 😛

I have tried to re-open the issue but i couldn't figure out how so i assumed it was developers/admins that only can do that

Thanks in advance.