Google Home, Chromecast Audiogroups and Spotify Connect Issue

[Kupferbart1]

Following problem:

When I initiate music streaming from spotify with my Google Home for a Chromecast Audiogroup, and the start the Spotify app on my phone, Spotify Connect asks me if I want to continue listen on the Google Home the stream was initiated on, instead on the audiogroup, even though all speakers are currently streaming.

I am also not able to control volume with the volume buttons on my phone.

Hope this can be resolved!