When mobs dismount minecarts, they can be placed inside blocks

The bug

In snapshot 23w41a, carts where changed somehow so mobs that dismount carts now can be placed inside of blocks when before they needed air at the location.
Also players can clip through the floor using this.

A video of this issue can be found here.

How to reproduce

1. Place and power an activator rail such that there are no valid surrounding blocks upon which the player can be placed
2. Attempt to enter the minecart
   The player may be placed within the block below the minecart