So if you've downloaded some of these playlists, this can explain the behavior you describe. This could usually happen if you downloaded playlists created by other users, Spotify created playlists that update often, Made for you playlists, Collaborative playlists, etc.
First of all, keep in mind that this can happen if a playlist you've downloaded has been recently modified, so the next time you open the app it will try to sync to reflect the recent changes in that downloaded playlists.
