Disclaimer: I work at Spotify, but not at music ingestion and classification. I can give you a very high level overview of why it's the case. Simply put, they

Disclaimer: I work at Spotify, but not at music ingestion and classification. I can give you a very high level overview of why it's the case. Simply put, they are different songs, and it's near impossible to recognize that they are the same song (at least not efficeintly across the entire catalog) due to a combination of any, or even all, of these factors: - they are on different albums. The albums might not be attributed to the artist. Or be a compilation, and attributed to many other artists - they may come from different sources and copyright holders - the metadata may be wrong, or just different (metadata is supplied by copyright holders, and it's often ... weird) - they may very well be considered different songs by most catalogs (a Japanese bootleg version that is 3 seconds longer is different from the European Best Of release etc.) - everything is the same except some of the people on the record (e.g. arranged by a different person, so attribution and royalties come into play) - ids, hashes, lengths, musical structure, or whatever internal systems use to identify, match, combine, and display music may all be different, or different enough to be classified as different songs - there might be not enough music classified in the genres you listen to to present you with a large enhanced playlist. This is an issue for most non-western music because western music is largely understood, catalogued and matched for most of mmore-or-less popular genres. And even there it probably mostly applies to US nad British music. You're looking for African jazz? Good luck. Internally it's likely just one big lump of music dumped by music providers.