included_groups=album give me all result and not only album

[Saluki]

Plan

Free/Premium

Country

Belgium

Operating System

Windows 10

My Question or Issue

I work  with angular and i make this :

getAlbumFromArtist(artistId: string😞 Observable<Album[]> {
  return this.fetchAllAlbum(`https://api.spotify.com/v1/artists/${artistId}/albums?included_groups=album&limit=50`, []);
}

 
But when i receive the result, I receive more than just the album (single, compil, ect is include)

Do you know what happend ?