Hi ​@Restub 

Welcome to the Sonos Community!

Sorry to hear of this issue you are having.

This is essentially by-design - when you play via Bluetooth, your Home Theatre primary determines that music is being played (as opposed to TV audio - it doesn’t actually know if music is playing), and as a result, the stereo audio is also played to your surrounds according to the Music Level setting in the Surround Audio section of the room’s settings.

However, when you play Spotify on your TV, the Home Theatre primary determines that TV audio is playing (again, it has no idea that this audio is in fact music) and as result, it only plays to the surround speakers when surround audio is played. What you do hear from the surrounds is a result of the stereo feed being up-mixed to include low levels of audio from the surrounds to make it sound a bit more enveloping.

You have a few options - to make things a bit more consistent, your could lower the Music Level setting so that audio from Bluetooth does not get played to the surrounds as much, or you could switch to playing either Apple Music or Amazon Music Unlimited on the TV - with spatial audio music playing, the surrounds will get included in the mix. Alternatively, if you were to play Spotify using the Sonos app, or to tell the Spotify app to play to Sonos (possible on the Android/iOS mobile apps, but I don’t know about the TV versions), it would play through the surrounds just as with Bluetooth.

I hope this helps.