Spotify Connect - Turn on device that music are not playing on it

[kelvinhk]

I have a LG Music Flow Soundbar HS7 as a spotify connect speaker device. But when I am not using the soundbar to play the music, say I just wanna play it on iPhone, once I clicked the play button my Soundbar will still be turned on and go into standby mode. The music did play correctly on my iPhone but the annoying part is even I am on street listening music with my earphone, the soundbar at home will be turned on for no reason. Is this a bug? iOS 8.4.1 with latest spotify app version