X-ray glitch when entering a boat/minecart while flying with elytra

The bug

If you fly with your elytra near a boat above bottom slabs, then enter the boat at just the right time, you will enter the boat in a strange way. You'll be able to see in an X-ray kind of way, but if you're in survival mode you'll start to suffocate unless you get out of the boat. However, this doesn't happen every time. You have to time it just right.

I think that Minecraft thinks you're actually in the ground, even though you're in the boat. That's why you'll suffocate, and that's why the X-ray bug happens.

How to reproduce

1. Place a boat on top of bottom slabs
2. Equip elytra
3. Glide toward the boat
4. Enter the boat while gliding
   The player may be positioned under the boat (allowing them to see underground), instead of positioning the player as they normally would sit in a boat