.

Cannot see any minecart in your screenshot.

This ticket is very difficult to comprehend, please use the Bug Report Guidelines Here when posting issues.

From what I can see in the pictures, it looks like what's happening is that the minecart's going too fast at that little circle in the top left of the 3rd picture, causing it to derail on one of the corners. It then flies onto the track it was just on, and the cycle repeats over and over. If that is what's happening, then it's not a bug, it's just the way minecarts work in the newest snapshot. You need to make sure the minecart isn't going too fast on corners or it will derail.