Minecarts not rolling when bouncing at angle

Put the summary of the bug you're having here

What I expected to happen was...:
A hopper Minecart rolling back and forth forever.

What actually happened was...:
The Minecart stopped at the top of each side!

Steps to Reproduce:
1. create a ramp (such as the one in the image attached.

2. Push a minecart

3. Watch as it gets stuck on either end, whereas in previous versions it would continuously go back and forth.