I've noticed this a few times when searching Spotify. I'll find my artist, however an album or track with be classified as their work when it is not. Example: Beach House. Today I got really happy seeing a new release by them, "Sunset." How could this be? Well, I quickly came back to earth. It is not them at all. Who, at Spotify, is in charge of this?
You can report any content errors/issues such as these directly to the Spotify content team using the instructions outlined in this topic. Once you have submitted a query, the content team will investigate and then pass any needed details over to the record label to request a correction/change if needed (so it can take some time unfortunately!).