Spotify, Sonos Play 5 and iOS 11.0.2

[kiddingguy]

I have a Sonos Play 5.

I use my iPhone/iPad as music controller for Spotify. I do not use the Sonos app for playing music.

When closing Spotify the music is still playing. I found out it’s not the buffer, but the musical control panel in iOS 11 which is still active and not closed/cancelled as well.

I guess this is a bug. But is it Apple’s of Spotify for not registering to the control panel as to close?