If you exit a world as a minecart turns a corner (on a track set up in a circle), when you rejoin the minecart wil be going in circles but off the track.

What I expected to happen was...:
I was just messing around using NBTExplorer so I could make the minecart turn into a spawner minecart.

What actually happened was...:
I couldn't get the minecart to turn into a spawner minecart, so I rejoined, and Inoticed straight away that the minecart was going in a circle, but in went right off the track.

Steps to Reproduce:
1. Place a minecart on a small circle of track, that has powered rails on it to keep the minecart going
2. Pause the game as the minecart is turning one of the four corners, and save and quit to the title screen.
3. Go back into the world.

*Evidence: Since the minecart world be moving, it would be impossible for me to put a picture here as the minecart would look like I just placed it by the track and positioned it. So I am sorry for no evidence. EDIT: I have some evidence attached now, it is from the real thing. Take a look at it!