The audio output has no sound from the audio-mezzanine-board headset connector with the rpb desktop image. For the desktop image we removed openbox and added xfce-base and pulseaudio-server. We can see from the pavucontrol the sound card is detected and indicator is moving when the audio file is getting played. The HDMI audio output IS working. Also the audio (headset jack) is working with the Debian image.
Please let us know if this is a known issue.