Steps to reproduce:
1. Create a new HDRP project
2. Create a Diffusion Profile
3. Assign it to a Lit Subsurface Scattering material
4. Click "Fix" when prompted with a warning to assign to HDRP asset
5. Save project and reopen it
6. Observe that the Diffusion Profile List is empty in HDRP asset

Expected result: diffusion profile reference should be saved in HDRP asset when reopening a project

Reproduced in: 2020.1.0a16, 2019.3.0f2
HDRP packages reproduced in: 7.1.6