TNT minecarts traveling through nether-portals can create lots of portals

In 1.21 Pre-Release 4, primed TNT that travels through portals can no longer destroy portal blocks. I suspect that this change was done to prevent repeatedly sending TNT through the portal from creating many (broken) portals on the other side.

However, this change was not done to TNT minecarts, which can be used for the same effect. This can be used for grieving a large area with relatively little effort.

How to reproduce

1. In the spawn chunks, build a dispenser repeatedly dispensing TNT minecart onto a rail leading into a nether portal.
   
2. Go through the nether portal yourself
3. Observe many nether portals being created