Wrong versions of tracks

[BanjoPM]

My band has an EP on Spotify that was digitally distributed by CD Baby. When the EP first went up on Spotify the tracks were correct, however I recently went to play the EP and some of the tracks are the wrong version. They are the unmastered version, which only a handful of people have, not even CD Baby. I thought it could be an issue with Spotify linking to local instances of the files, but the wrong verions are being played on multiple devices, across muliple accounts. How has Spotify got these versions and why have they overwritten them, so when other people play the track, it plays the wrong version?