Probably since the last update of Spotify the song title doesn't switch to the next song when playing on my smartphone. This does happen in the display on the bottom of the screen, with the player full screen and even in Waze. The next songs are being played correctly but with te title displayed of the first song that has been played in this view. When changing the view te title is being refreshed.
BTW Spotify also keeps playing after disconnecting from bluetooth since then.