The bug

Sides and bottom of trapdoors rotate illogically when opened and closed.

Possible fixes

I didn't find a way to fix all the problems, that's why I made three options:
MC-138280 Fix_1.zipMC-138280 Fix_2.zipMC-138280 Fix_3.zip

I took into consideration 3 things (which can be compared in the image below):
. Rotation: if the sides follow the rotation of the trapdoor.
. Hinges: if the texture of where the hinges would go remains still when the trapdoor is opened and closed (like doors).
. Direction: if the four sides are in the same direction at the same time.

• Fix_1: The sides follow the rotation of the trapdoor and the 4 sides always point in the same direction, but the hinges do not stay in place.
• Fix_2: The hinges stay in place, but the sides of the hinges do not follow the rotation of the trapdoor and the 4 sides point to different places.
• Fix_3: The hinges stay in place and all 4 sides point to the same direction at the same time, but the sides flip when the trapdoor is opened and closed.

Personally I prefer Fix_1 as it allows me to do more types of columns and because the only problem it has is with the hinges (and since trapdoors don't have hinges, like doors, this really wouldn't be a problem IMO)

And about what I changed, I had to divide the file "template_orientable_trapdoor_open.json" into "template_orientable_trapdoor_bottom_open.json" and "template_orientable_trapdoor_top_open.json", it was necessary to differentiate those two states, otherwise I would only have been able to fix one of those (half:bottom or half:top). Then I changed some uv values and linked the files to the new templates.