In creative and survival minecarts would not go around curves. This occurs not on the positive x negative z but in the three other cases the minecart just goes back. And in the case of going from positive z to negative x the minecart stops at the corner. I have video recording of the bug.
I hope this helps and has not already been submitted.
thanks for the amazing game!
Environment
Windows 10 Home
I7-8750H 2.20 GHz
64bit operating system
Duplicate of MC-144605