Whenever I edit in Multitrack, I generally have my blocks of dialogue as different clips. So when I auto-duck the music track, I want it to use the gaps between the clips as its basis for ducking. The clips themselves have wall to wall dialogue, no need to try to duck within the clip.

There should be a checkbox maybe to "use clips for duck detection" or something so it's only ducking the music under clips and then back up to full volume in the gaps.