Minecrafts don't pass along curves , if it's not a south-east curve. They bounce back as if there were a barrier there.
MC-144943
Minecarts bounce back at curves
Resolved
Duplicate
3
The same for me. In addition, the minecarts have disappeared in the Nether at least near the portal. Maybe a connection with the bug https://bugs.mojang.com/browse/MC-143404 which occurred at the same time at this portal with a horse.