spotify over rides my car audio

[bklyndave]

after i listen to anything on spotify, mostly podcasts. i hit pause and then close the app on my android phone. For some time, at least that day and often the next day, when i have my bluetooth as my source, it automatically starts replaying spotify. the only way to get it to stop playing is playing another app on my phone. but even when i have another app on and i have closed spotify, if i take a call and then hang up the audio goes right back to Spotify. so i have again start the other app. i can't turn it off, pause it or close it...because i ALREADY did that. 

ideas? suggestions?

in the USA, free plan on a samsung galaxy 8+ connected to a subaru bluetooth