Apple CarPlay - same track plays on phone connection

My car is fitted with Apple CarPlay which I love so far. And I subscribe to Apple Music.
However, sometimes when I connect my iPhone 6 Plus and the CarPlay system boots up, before i’ve selected anything on screen one particular track from my music library begins to play. It’s a track that I rarely play, but don’t want to delete it. If I select the Music icon or a radio tuner app I can select something to hear and the track stops, but inevitably next time I connect up it starts playing again. It’s not that big of a problem, just intriguing!
Anyone any idea why this happens?
Thanks.

I'm not sure of a fix, BUT I have a friend with Carplay who has complained about the same issue!