I think the friend graph explains most of these away, along with coincidences. If your Spotify friends listen to a specific song, it kinda makes sense for them

I think the friend graph explains most of these away, along with coincidences. If your Spotify friends listen to a specific song, it kinda makes sense for them to recommend it to you as well. They may have also given their friend "the aux" at some point which would train the algorithm on their music, so it's just bringing those songs back up (this one happens to me _a lot_)