iOS App Filter incomplete

[macblum]

Plan

Premium Family

Country

 Germany

Device

iPhone 8

My Question or Issue

 I have downloaded two big playlists (1000 + 2000 songs) to my iPhone because I wanzt I use the Spotify App as my favorite offline music player.

So I use the filter option in the different categories of my library, f.e. Artists/Filter/Downloads to see only my local songs. But the filter list is incomplete. There are only a couple of artists (about 10 to 12), but there should be all artists of the 2000 songs playlist (and that should be maybe more than 100...).

The same problem ist in the filtered albums category.

The playlists are downloaded without any losses. That makes no sense and Sontheim App is not very comfortably to use for may local stuff.

Do you know the Problem and have you any idea how I could solve it?

thanks and best,

Andreas