Also was on 1.7.2 but couldn't type that.
Also you have not really explained well enough
This is probably a glitch that is unfixable, as the terrain is generated to be random, not to obey the laws of gravity.
This is also not a bug, it is intentional.
Can you try to make your typing accurate, as it took me a while to work out what you said.
ok
Thank you for pointing that out. I will do in the future
All the Iron Trapdoors should have been deleted when you went on 1.7