When Minecarts goes into a curved rail, stops in mostly unexpected ways.

What I expected to happen was...:
The Minecart should advance and turn as expected.

What actually happened was...:
On most directions and angles, the Minecart didn't do as expected and stopped, derailed or got the other way.

Steps to Reproduce:
1. Build a circle rail loop and place a Minecart on it.
2. Push the Minecart and watch it go