How to reproduce:
1. Open the user's attached project
2. Select 'Edit' > 'Preferences...'
3. In the Preferences window select the 'HD Render Pipeline' section
4. Set 'Matcap intensity scale' to anything other than 1
5. Close the Preferences window and the project
6. Reopen the project and the Preferences window
7. Observe the 'Matcap intensity scale' value

Expected result: The newly set 'Matcap intensity scale' value is saved
Actual result: The 'Matcap intensity scale' value is reset to 1 once the project is reopened

Reproducible with: HDRP 7.3.1, 7.4.3 (2019.4.11f1), 8.2.0 (2020.1.7f1, 2020.0b4), 10.0.0-preview.26 (2020.2.0b4)
Cannot test with: HDRP 4.10.0-preview (2018.4.27) (there is no 'HD Render Pipeline' section in the Preferences)