I came to confirm this. What Mark Veldhuis said appears to be true: When you exit your minecart you are teleported instead of just coming out next to the cart. I fell through a wall and into lava in my survival world when exiting my minecart, not the best moment I can tell you. I have since confirmed it multiple times. Placing 3 rows of 2 high blocks behind the 1 block wall prevented me from falling through, but this cannot be a solution for such an obvious bug. If it helps I will make a video of it.
I came to confirm this. What Mark Veldhuis said appears to be true: When you exit your minecart you are teleported instead of just coming out next to the cart. I fell through a wall and into lava in my survival world when exiting my minecart, not the best moment I can tell you. I have since confirmed it multiple times. Placing 3 rows of 2 high blocks behind the 1 block wall prevented me from falling through, but this cannot be a solution for such an obvious bug. If it helps I will make a video of it.