I'm trying to set B703/HN-B701 bluettoth headset as primary sound output device after connect. I moved it to first position in all sound categories. But, even after I clicked to "apply", primary soundcard was still used as audio output. Only after pressing "left" and "right" buttons produced sound in headset. After I disabled "Internal audio analog stereo", I can hear sound from headset. After turn off and reconnect ganiture, there was no any devices in "Device preference" tab. If I relaunch system-settings, headset audio source was still in second position. And I have to again turn off "internal audio analog stereo" to be able hear something from garniture. Can I send you some logs to help fix this? Hint: after installing & configuring Blueman from GNOME, issue was fixed, so, I think, some specific pulseaudio configuration needed
Closing, given the age of this report. If you can still reproduce this in an up to date KDE Neon install, feel free to re-open this report