The Problem with Spotify's AI

One day I was sitting at the table with my sister and we were showing each other songs we like on Spotify. I saw on her phone she was subscribed to one of the same Spotify-created playlists that I subscribe to. I knew the song I wanted to show her was on that playlist, so I asked if I could look for it on her phone and looked through that playlist I was subscribed to. I scrolled through the entire playlist, some 200, songs, and I couldn't find it. I thought, then I went to the search bar and searched the name of the song… No results.