Issue with exporting character in unity

Hello Support Team,
I am experiencing a critical issue when building my Unity project for Android VR (Oculus Quest). My character, imported from Character Creator 4, displays perfectly in the Unity Editor, but fails to render in the final build.

Here is a summary of the problem and the steps I’ve taken to diagnose it:

Initial Problem: The character is invisible in the Android build, except for its eyes. This suggests a shader or material issue.
As a test, I replaced all the character’s materials with the standard Universal Pipeline/Lit shader. With this change, the character appeared correctly in the build. This confirms the issue is isolated to the CC4 shaders.

My goal is to use the high-quality CC4 shaders. I tried to force the shaders to be included in the build by adding them to the “Always Included Shaders” list in Project Settings > Graphics. However, this caused the build to fail with the following critical error:
Plain Text
An asset is marked with HideFlags.DontSave but is included in the build:
Asset: ‘Library/unity default resources’
Asset name: Hidden/InternalErrorShader

This error implies that one or more of my materials are defaulting to Unity’s internal error shader, and manually including it in the build is not the correct solution.
Could you please provide guidance on the correct workflow for ensuring the CC4 URP shaders are properly compiled and included in an Android VR build? Is there a known compatibility issue or a required project setting I might be missing?
Thank you