I dug into this more deeply and recognize where a prerequisite for proper recognition is installing a CHD-Compatible core. I can also understand if some of the images have unique identifiers that aren’t in the database.
In testing, I am getting different results between Windows, Lakka, and Android for the exact same content & cores. For 12 SegaCD discs where both PicoDrive (not CHD-compatible) & GenesisPlusGX (CHD-Compatible) cores were installed. With the exception of Lakka whose cores are installed in the OS image (you can’t update them online/within Lakka), Windows and Android’s cores were updated just prior to testing:
Android - Retroarch 1.8.1 - 0 added to playlist
Lakka - Retroarch 2019-11-04/odroidXU3 - 12 added to playlist
Windows - Retroarch 1.8.1 - 8 added to playlist
Android reports in the log
“Comparing with known magic numbers…”, “Could not find compatible system”, no matches
Lakka reports in the log “Comparing with known magic numbers…” then matches 12 of 12.
Windows reports in the log “Comparing with known magic numbers…” then matches 8 of 12.