duplicate songs on never synced iPhone 7

Many people seem to have duplicate songs on their iPhones related to syncing with a computer, but I have never synced my phone, only backed it up via iCloud. Each song appears twice, and plays twice, so I either have to listen to it twice or skip forward. The problem also appears on third-party music players, not just the Apple player. I'm worried that this goes beyond the display, and each song is actually duplicated in the phone, eating up my memory. This occurs on the majority of my music, but is not universal. My most recent purchases do not have the problem, though they get infected as they age. It does not affect films, TV shows, or other purchases. I have found no way to clean it up. The songs do not appear twice in the iTunes store.