Currently if I am listening music in the computer, the phone makes a notification sound multiple times (around 8 times) each time a new song is played or a new action is made in the spotify web player.
If you need any more detail I will provide it gladly.
Version Spotify app: 18.104.22.1688
One plus 3T
Chrome web player (haven't tried other, but the problems sometimes also appears when i am listening only in the phone)