Steps to reproduce:
1. Open Package Manager
2. Go to All Samples tab
3. Find and Import Renderer Shader User Value Samples
4. Open Agora.unity Scene (Assets/Samples/High Definition Render Pipeline/17.5.0/Renderer Shader User Value Samples/Scenes/Agora.unity)
5. Observer the Console window

Actual results: “Prefab instance problem. Missing Prefab Asset” errors are thrown in the Console after opening Agora Scene
Expected results: No errors are thrown in the Console window after opening Agora Scene

Reproducible with versions: 6000.5.0a8 (d36222f39966), 6000.5.0a9, 6000.5.0b1
Not reproducible with versions: 6000.4.1f1, 6000.5.0a7 (0841031ff752), 6000.6.0a1
Can’t test with versions: 6000.0.71f1 (Renderer Shader User Value Samples not available)

Tested on (OS): macOS Silicon Tahoe 26.3.1 (a) (M1)
 
Notes: If importing from the nested HDRP > Samples > Renderer Shader User Value Samples entry, the sample may not fully import on the first click, after importing again, the issue no longer reproduces.