Mopidy Discourse

Play song from Spotify App on MusicBox

Hi, just tried the Pi MusicBox with Spotify Connect. In general in the spotify app of my mobile I can change the audio output to MusicBox. But once I’ve done that I can’t select other titles.
What works if I skip forwards or backwards if I selected an album - then the next or previous title is played. Same to Spotify playlists. But if I start a new search and select a title it is not played on the MusicBox. Instead the current title is restarted. I can solve this by changing the output to my phone and then switch back to MusicBox.
Is this problem already known? How can I solve it?