We have a scene where the the CC4 URP shaders are working reasonably well in Metal Rendering with Compositor services.
When we switch to Reality Kit, the shaders give a number or errors/warning about missing attributes which leads to unusable materials. We are working with Reallusion CC4 characters and trying to find optimal shaders to give us some fidelity.
My best guess is that you’re getting the “fallback” shader conversion behavior (Project Settings → PolySpatial → Fallback Shader Conversion), which is treating the shader graphs as it would standard shaders like URP/Lit. This might be because the shader graphs failed to import correctly–in which case you might try reimporting them–or because they’re loaded from an asset bundle, which we don’t currently support for shader graphs with RealityKit.
If reimporting doesn’t help, feel free to submit a bug report with a repro case and let us know the incident number (IN-#####) so that we can investigate.