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!).
This issue is rooted a little deeper than just multiple artists on the same page. Spotify currently does not have a way in the clients to separate artists with the same name, meaning anytime this happens the artists get merged onto a single page. There is a discussion about it over on the Ideas Exchange here.