artist folder is ignored when it contains just a single album



I have a problem scraping my music into the musicdb. (I am doing it all new, coming from Leia, new tagging etc)
Before I spend more time investigating it (affected kodi versions, studying kodi logs) I ‘d like to kindly ask if there is a known bug here.

Problem:
When I scrape my music, only some artists are showing info and pictures.
What I found so far, all artists that doesn’t show information have just one album within their folder.

This is my folder structure: (no $ of course, they are just placeholders here)

music:
         $artist/
                 artist.nfo
                 folder.jpg
                 clearlogo.png
                 fanart.jpg
                 fanart$.jpg
                 $album/
                             CD$NUMBER/                         
                                                  $tracks.whatever
                                                  folder.jpg
                                                  discart.png
                                                  album.nfo
                     
when $album == 1 everything in $artist is ignored. This is also true when i try to fix things manually on the respective atist info page. artist with 2 or more $album will show their $artist folder as source folder, so I can pick e.g. clearlogo.png.Artist with only one $album will show the $album folder as their source which is of course empty except the CD$NUMBER Folder.

I have yet to test if this also happens when I use the seperate artist folder (I’d like to avoid that, since I want to use that only for “virtual” artists), or if I remove all nfo files and let kodi scrape everything online (like to avoid that too, I have reasons for local nfo and artwork)

Kodi Version is 21.1 flatpak
Tracks are tagged using musicbrainz picard + mp3tag, mostly flac files.