Steps to reproduce:

1. Create a new URP project
2. Window > Package Manager > ShaderGraph > Samples
3. Import Feature Samples
4. Delete the Feature Samples folder
5. Reimport Feature Samples

Actual results: 

 
{code:java}
Sub Graph at Assets/Samples/Shader Graph/17.0.3/Feature Examples/Custom Lighting/MainLight.shadersubgraph has 1 error(s), the first is: Validation: Source file does not exist. A valid .hlsl, .cginc, or .cg file must be referenced
UnityEngine.GUIUtility:ProcessEvent (int,intptr,bool&){code}
 

Expected results: No error

Reproducible with versions:

• 6000.0.23f1, 6000.0.22f1 - only this error occurs
• 6000.0.21f1, 6000.0.5f1 - this error occurs alongside multiple others

Not reproducible with versions:

• 6000.0.4f1 - different errors on import, no errors on re-import
• 6000.0.0b16, 2022.3.49f1 - no errors

Can't test with versions:  2021.3, not supported on Ubuntu 24.04

Tested on (OS): Ubuntu 24.04