CSG shapes get culled (double?)

[fire]

Tested versions

I suspect it's a doubles problem but investigating. I'm posting it here to keep track of the investigation. I can't tell if it's our fork or master.

• Not Reproducible in https://github.com/godotengine/godot/commit/c7f56d327d265fa7b2541fe7c5e6cc1730661749
• https://github.com/V-Sekai/godot/commit/45f07c4be4ab6007233a2ffb73d05747f018d834 (doubles)
• Not reproducible in 4.2

System information

Mac Mini, Apple Silicon, M2 Pro

Issue description

CSG shapes get culled. It's somehow related to occlusion.

https://www.youtube.com/watch?v=gQND11TyH-4

Steps to reproduce

1. open res://game/sandbox.tscn in the editor
2. move around
3. see the csg vehicles disappear

Minimal reproduction project (MRP)

godot-crappy-contraptions-main.zip

[fire]

It might be precision. Clay mentioned that it could be related to one of the prs for "mirrors" support with the modified projection, but trying to narrow down the problem.