The post was about the minecarts not going through the portals, but you just have to wait 30 seconds
Comments 3
invalid, after using a nether portal none player entities have a 30 second cooldown before being able to use one again. (they must be not touching portal blocks for the cooldown to start)
The video shows intended behavior; the minecart is still on portal cooldown, and due to MC-5686, it always will be for as long as it remains in the second portal. Whether this "mechanic" is desirable is something that can be discussed on the feedback site/Discord.