When using Spotify, as a streaming service, the volume levels on the 2 x Sonos One keep changing.

In Spotify, the volume levels are automatically adjusted to ensure a consistent volume for ALL tracks. 

Sonos app FAILS to maintain consistent volume levels.

This is a MAJOR fault with Sonos, and one that will lead me to sell my purchase and replace it with Bose or similar. 

Come on, Sonos, this issue has existed for FAR TOO LONG.