RTX/PBR broken in specific worlds only after GDK version — PBR textures not applied (only vanilla diffuse) + Vibrant Visuals cannot be enabled

Main Description

After updating to the latest GDK version of Minecraft for Windows,
ray tracing works but PBR materials no longer apply in specific worlds.

The issue is not limited to user-created worlds:
even the official NVIDIA RTX worlds show the same behavior when opened after the bug appears.

The following symptoms all occur together, suggesting they are related:

1. PBR does not load in affected worlds

• Metallic blocks (iron, gold, etc.) no longer reflect light.

• Smoothness/roughness maps and normal maps are ignored.

• Blocks appear as flat “vanilla diffuse” textures, even though RTX lighting is active.

2. Light-emitting blocks no longer glow properly

• Lamp blocks, redstone lamps, glowstone, etc. no longer emit PBR-based glow.

• Light behaves as if PBR data is missing.

3. “Vibrant Visuals” cannot be enabled in those worlds

• The toggle is disabled only in the affected worlds.

• In normal (newly created) worlds the option is available.

4. NVIDIA official RTX maps show the same broken PBR behavior

This suggests that the issue is not caused by custom resource packs,
but by PBR initialization or world-level graphic metadata failing to load.

5. New worlds created after the bug do work correctly

With the exact same settings, resource packs, and GPU driver,
PBR loads normally in brand-new worlds, so the issue seems tied to
world metadata or its PBR cache.

Why this is a problem / Why it seems like the same root cause

All symptoms point to PBR not being initialized at the world level,
while RTX lighting (GI, shadows, reflections) still works.

This strongly suggests a PBR metadata loading failure introduced in the GDK build,
affecting some worlds but not others.

Expected behavior

• PBR materials (metalness, roughness, normal maps) should load in all worlds

• Light-emitting blocks should glow

• Vibrant Visuals should be toggleable

• Official NVIDIA RTX worlds should always load full PBR correctly

• Old worlds should behave the same as new worlds

Notes

• GPU: RTX 5060 Laptop

• Drivers updated

• RTX lighting works perfectly (GI, reflections)

• Only PBR data fails

• Reinstalling resource packs, resetting settings, and importing/exporting worlds did not fix it