So basically on my Spotify free mobile account, the songs always play in order. This has only happened to me recently, and only happens to my playlists. (Not public ones.) However, I can choose which song it plays, and can rewind the song, which is strange, because I don't have Spotify Premium. I still want to have the feature to shuffle though. Additionally, the shuffle play button only says 'play' now. I'm not sure if this information helps, but I hope that someone can find a fix.