Pulseaudio is not installed by default. If you are using bluetooth audio, then we recommend you remove pulseaudio and use bluez-alsa instead. To remove pulseaudio and the deprecated a2dp package:
sudo apt-get remove a2dp-app-osmc
sudo apt-get remove --purge pulseaudio
Apart from that, it seems strange you’ve only got this issue since connecting in the soundbar. That should not affect the options you see in the audio settings. Let us know if removing pulse fixes things.