Pregenerated doors are 2 top-of-the-door blocks (witnessed in stronghold)

Found my way into a stronghold in 14w27b. Seed 4794933921088204539 Coords x629 y17 z549. Screenshot included. I noticed all the strongholds' doors are 2 top-of-the-door blocks instead of normal doors. So I switched to creative to give myself a door and place it. Placed doors turn out normal. It's just pregenerated ones that are the problem. Trying to interact with the broken doors (asking for trouble I know) they have a hitbox on the top block only, and clicking on it makes the noise but doesn't open the door. Using gamemode 3 to ghost thru the door, switching back (creative) and trying to open the door from the far side crashed the game the first time I tried it but didn't the second time. The second time it crashed when I clicked on the bottom.