Isn’t Background sound meant for music to be playing all the time and to be looping? I mean, wouldn’t it be easier for voiceover to use a separate normal audio object for each page so you can use all the usual features?
It seems to be a bug that it’s possible to target the background audio in actions. This is also new in Lectora 17. Although of course it would be nice to make the background audio controllable with the normal actions.
Here’s your sample using Darrels code to play / pause. It also prevents the audio from looping. The background audio gets a different id on each page that contains the page name. It would be easier to control if it always had the same id.