Why can't I set a default output audio device in Ubuntu 19.10?

My laptop with Ubuntu 19.04 detected and set my HDMI output on every boot. But since I upgraded to 19.10, I need to set it manually every boot as follows:

From

to

I already tried every single solution proposed in How do you set a default audio output device in Ubuntu 18.04?, but apparently there's something different in 19.10. What I did specifically:

1. pactl

$ pactl list short sinks
9   alsa_output.pci-0000_00_1f.3.hdmi-stereo-extra1 module-alsa-card.c  s16le 2ch 48000Hz   SUSPENDED

$ pactl set-default-sink 'alsa_output.pci-0000_00_1f.3.hdmi-stereo-extra1'

2. Add either the device number and device name in /etc/pulse/default.pa like:

set-default-sink 9

and

set-default-sink alsa_output.pci-0000_00_1f.3.hdmi-stereo-extra1

and

set-default-sink 'alsa_output.pci-0000_00_1f.3.hdmi-stereo-extra1'

3. Comment the line load-module module-switch-on-connect.

4. Switch profiles in PulseAudio Volume Control to HDMI2.

None of these persisted after reboot.

This is a bug reported here three days ago:

• Audio / Sound reverts to HDMI when power event occurs

PulseAudio reverts the sound to HDMI all the time when a HDMI related power event occurs. That means, although I have set another USB sound device plugged in and set as default under sound settings, when an application like Kodi or the system shuts off the HDMI monitor and I reactivate the monitor, the sound is set to HDMI output again and again.

That probably has to do with the fix to the reported Bug # 1711101 and definitely not happened at Ubuntu 19.04. I switched to Ubuntu 19.10 two days ago.

Setting the USB device as default does not help, even when done by PulseAudio mixer (gui) and removing HDMI output from the alternatives option.

Only one person is effected by the bug (on November 4, 2019). Visit the link, click that it effects you and subscribe to the bug email.

11 people are now effected as of November 8, 2019. Comment #11 presents a solution though:

I think i found a solution. I'm commenting this lines

#load-module module-switch-on-port-available
#load-module module-switch-on-connect

in etc/pulse/default.pa and all work for me.