Door literally on a roof

[Danaka]

Link to Clip (youtube)

Managed to reproduce this door on the roof.

Looks as though it would allow it as shown earlier in the clip however only when moving forward specifically as I did would it let me actually place it. (Very weird!)

Note. To add to the weirdness if I get increased expansion it stops it from working like this (at least from where I'm standing)

 

[Danaka]

Checked in new patch and this is still possible (Other weird doors on my channel are still possible too) - This clip shows how to reproduce it a LOT easier as I'm moving in the previous one :

Link to Clip (youtube)