LTS 26.2 enivronment preview bug

[GuySevern]

Tested versions

Redot Engine LTS v26.2.beta.1.mono.official win64 x86

System information

Window 11 Home, Nvidia GTX 5060, CPU i5-14400f

Issue description

This bug is related to the environment preview shader. When it is active in a new project it can't render the light properly and leaves hard black shadows. When loading older REX or 26.1 LTS projects the environment node present is corrupted and must be reset. This bug can be corrected by turning off environmental preview or creating a brand new environment node in older projects.

NOTES:
This bug coincides with a major windows update.
This bug has spread to my builds of REX also, and 26.1 LTS
This bug does not appear in Godot 4.6
A similar shader issue also appears in the import screen. May not be related.

Steps to reproduce

1. create new project
2. create any mesh object for the scene, ordinary CSG box works well.
3. make it bigger, 10m x 10m
4. add standard shader to the Mesh object. Then give it an albedo texture, and a normal map
5. turn on 'toggle preview environment' on the tool bar, if not already active.

Minimal reproduction project (MRP)

issue-enviro.zip

[Shakai-Dev]

I'll look into this