Album Artists not limted to Album Artists

[annomatik]

Describe the bug

For my classical music collection (a library view in Lyrion), I use composer names for Album Artist as well as Composer. This mostly works, except for some artists. They show up in Album Artist view, even though I have not specified them as Album Artists.

So, right now, I'm using:
ALBUM ARTIST=Composer
COMPOSER=Composer
ARTIST=Solist (Instrument); Vocalist (Tenor); Orchestra

For example, Bryon Janis (Piano) in my oppinion should only show up in ALL ARTISTS, not in ALBUM ARTISTS as I haven't specified him in any album as Album Artist. Yet...

To Reproduce
Steps to reproduce the behavior:

1. Go to my Lyrion instance ( ;-) )
2. Select the Classical Library View
3. Go to Album Artists
4. See, that there are also "regular" artists (not all of them), the view is not limited to album artists.

Expected behavior

Only see artists specified in album artists

Screenshots

System Information (please complete the following information):

• OS on which you're running LMS: Docker (Synology DSM 7.2.2)
• Web skin used: Material
• Browser Crome
• LMS Version 9.0.2
• Player(s) involved: Squeezeplay, Squeezebox Radio / Boom / Touch

Additional context
Crossposted earlier in forum: https://forums.lyrion.org/forum/user-forums/beginners/1770799-album-artists-shows-regular-artists
I'll happily post additional info when you tell me what you need.