After and update on May 2023 to Spotify's guidelines regarding the accepted metadata, Spotify now reserves the right to reject any and all releases which includes the artist name in the metadata of your release.
Since Spotify adds the credit of the features and contributors, like composers, lyricists, etc., it requires to assign the credit to an ID on their platform, this can be found with the information filled on the metadata of your release. By adding the artist name of said contributor proper credit and/or monetization cannot assigned as to said person, this hinders your release growth.
To prevent this, we recommend adding the full legal name of all contributors, so your release doesn't get rejected by Spotify.
My contributor/I wish for anonymity on my content, what can I do to not get rejected?
We understand that some people would like to use their artist name, in a way to explore and grow your content as you pursue your musical career.
In order to prevent the rejection of your release, we recommend using a pseudonym which can be considered a 'real name', this will allow to give credit to your contributors and your content won't be hindered.
Alternatively, if the contributor and/or you don't wish to add a pseudonym, in order to fulfill our agreement to publish your content, we'll be allowed by you to modify the metadata of your release in order to comply with Spotify's guidelines.