Steps to reproduce:

1. Build the following setup in a world with the Minecart Improvements experiment enabled:
   
2. Push the minecart a bit
3. Break the powered rail underneath the minecart
4. Break the block underneath the minecart

Observed result:
Whatever the minecart's x, z values were, it will snap onto the center of the rail.

Expected result:
The minecart will keep its x, z values like in 1.21.1 and below.