The menu point ""Update in background" has 3 settings: None, Graphics only, Graphics and sound.
This setting corresponds to "pauseMode=" in the user_settings.DayZprofile file, witth None = 0, Graphics only = 1, Graphics and sound = 2.
Changing this setting to "Graphics and sound" while ingame works correctly and sets it to 2 in the file.
But starting the game sets it back to "Graphics" only.
Edit:
The issue is caused by using the -nopause launch parameter or ticking "No Pause" in DZSA Launcher.
Ticket can be closed.