Version tested: 2021.2.0.a19 + 12.0.0 (Master)

Steps to reproduce:

1) Create an empty HDRP project or a template
2) Create a new Lit SG
3) Open it, observe the star next to it's name, meaning the file is dirtied and needs to be saved
4) Click save asset, observe that star doesn't go away
5) Click save asset again, observe that star is gone

Note: doesn't happen on URP. In HDRP file is dirtied right away after the first opening.