So regarding the Nareh Arghamanyan album unfortunately I cannot see exactly why it failed because your Fix Songs Report 18 task started at 12/07/2024, 14:19:45 but because our logs are circular I can only see back to 12/07/2024 15.35.48. If you reran Fix Songs on just this album and then rerun Create Support Files I could give you a definitive answer.
But I can give you an idea, SongKong matching is primarliy album based and tries to match groups of songs to albums. Your album metadata is a bad match you have album title as Rachmaninoff, Sergei - Piano Works (DSF) when actual title on MusicBrainz is Morceaux de fantaisie / Études-Tableaux / Corelli Variations.
Also you have album artist as Arghamanyan, Nareh instead of Nareh Arghamanyan and composer as Rachmaninoff, Sergei instead of Sergei Rachmaninoff so this makes artist matching sub-optimal as well.
The tracks that have been matched MusicBrainz Song Only have a matching Acoustid but the non matched track do not (1 and 13). So I guess we managed to match by Acoustid rather than by the metadata but those two tracks have a new acoustid that wasnt currently in database and hence linked to any MusicBrainz recording and this prevented full album match so therefore even the songs that did not match only had song details added rather than album details.
I suspect if you ran against this album with Preview disabled then ran a second time there would be enough infomration added first time round to get album match second time. You would also be able to force match using Match to One Album and specifying the MusicBrainz Release Id.
I will look at some of your other examples to see if in logs.