I have noticed that when a slash region has the “show other voices” property enabled, any change to either the “beam grouping” or “note grouping” notation options causes the shown voices to be hidden again. The property still appears enabled in the lower zone, but the other voice in the slash region is hidden. To show the other voice again, I have to disable the property, then enable it again.
Slash Region.dorico (2.1 MB)