Put the summary of the bug you're having here

Describe what you thought should happen here

I send a minecart (duplicated bug with any other cart) into the nether, it should follow an automated rail to another nether portal back to the over world

Describe what happened here

minecart follow the rail but do not teleport back to the over world. It only can teleport after you break it in the nether and put it back on the track (temporary fix). This can happen in reverse, sending a cart from the nether, it will teleport to over world but it cant be teleport back to the nether unless you break it.

Steps to Reproduce:
1. make a nether portal
2. go to the nether and make another portal back to the over world
3. connect the 2 portals with a railing system
4. send a cart from the over world to the nether
5. cart follow the rail in nether but go through the teleport instead of teleport to over world.