"SCRIPT ERROR: Parse Error: Cannot find property" for engine customization only after exporting. | Godot Engine | Page 1

I added directional helper methods to the Transform C++ classes, and thought everything was fine since it tested okay in the editor. Here are the changes I've made:
https://github.com/godotengine/godot/pull/100385
After exporting, however, I get errors such as these:

          at: GDScript::reload (res://archetypes/platform_set/math_platform_set.gd:195)
SCRIPT ERROR: Parse Error: Function "up()" not found in base Transform3D.
          at: GDScript::reload (res://archetypes/platform_set/math_platform_set.gd:195)```
What am I missing? Also bonus if there's anything else I should improve on my PR.

GitHub

Add helper methods for directions to Transform3D and Transform2D by...

This was added in response to this related issue that I came across when experiencing the same issue.
This is my first time committing to Godot, or any open source project for that matter, so pleas...

I should note these errors appear for both Windows and Web5 builds.

#"SCRIPT ERROR: Parse Error: Cannot find property" for engine customization only after exporting.