How to reproduce:
1. Open the attached project "Hair Transmission problem.zip"
2. Open the "OutdoorsScene" Scene
3. Open the "Test Hair" Shader Graph from the Assets folder
4. Make sure the Material Type is set to "Physical"
5. Open the Scene window and position the Camera so the "GameObject" with the attached hair would block the sun
Expected result: The hair appears gray
Actual result: The hair appears white and shiny
Reproducible with: 12.0.0 (2021.2.0b15), 12.1.6 (2021.2.19f1, 2021.3.1f1), 13.1.7 (2022.1.0b16), 14.0.2 (2022.2.0a10)
Could not test with: 7.7.1 (2019.4.38f1), 10.8.1 (2020.3.33f1), 11.0.0 (2021.2.0a3) - Material Type selection in the Shader Graph is not available