After flying with the elytra, you go to land. After you have landed, however, you can go through one block. I mean this as in you've placed down two blocks, and broke the bottom one, you can now walk through the top block.

How to recreate:
+ Fly around with the elytra for a little bit.
+ Land.
+ Look for a block that is one above the ground.
+ Walk towards it and see if you have walked through it.

I'm not sure if this was intentional or not, but I've often found myself stuck in a block and start suffocating. But I hope someone looks into this, or at least tell me that it is intentional.

Thank you.