This may or may not be effected with the elytra but as I was making a stair way outside my castle walls I managed to hit the roof part where I cut out of the wall. usually the game stops you dead in your tracks when moving forward but as of 1.2 if you move forward and hit the wall with you head it'll head glitch you into the block and take damage. It also happens when you stan in a 2 block high room and jump to the roof. The player will take damage and glitch through the wall as if its transparent.

No addons were used.