When a minecart is travelling along a minecart track, with or without a mob inside of it, once it reaches the end of the track, it sink into the top layered block as if it is not there. If there is a mob in the cart and you hit the cart to make it disappear, then the mob will trapped and killed. (View attachments for better description)

*What I expected to happen was that the minecart would stay above the top layer

*What actually happened was the minecart fell through the top block (layer).

Steps to Reproduce:
1. Build a simple minecart track
2. Place a mob on the track
3. Push the minecart into the mob to make it pick up the mob (Optional)
4. Then make the minecart go off the track
5. Hit the minecart to make it disappear