This is driving me nuts forever
Mine does the same but it plays a "random" song and always from the last service used. A blank song would not help me at all. If I played Spotify then it will start playing Spotify when the car connects via bluetooth. Even if the radio is off. If I don't notice this on time it will use my bandwidth for hours. I have to switch to a local playlist every time I leave the car and used Spotify. And switching off "Autoplay" in my car (and autoplay exists in the settings) does not do anything.
I guess I have to live with that.