Shader fails to compile when its material is specified in model's import settings

[Delt06]

[Worker0] Shader error in 'DELTation/Toon Shader': Couldn't open include file 'Packages/com.deltation.toon-shader/Assets/DELTation/ToonShader/Shaders/ToonShaderInput.hlsl'. at line 198

[Delt06]

Restarting the project resolved the issue.