Mix volume between background audio and video clip audio

Is it possible to fade in/out the background audio track while certain video clips are playing their audio?
This is how I am currently attempting to do that - by setting the mixVolume of the clip to 1 if it is marked as requiring audio.
As it is now, the background audio file just plays at full volume and the audio from the video clips isn't audible.

await editly({
  outPath,
  audioFilePath,
  loopAudio: true,
  keepSourceAudio: true,
  audioNorm: { enable: true, gaussSize: 3, maxGain: 100 },
  clips: [
    ...schedule.map(take => ({
        layers: [
          {
            type: "video",
            path: pathForLocalTake(take._id),
            resizeMode: "contain-blur",
            mixVolume: take.prompt.requiresAudio ? 1 : 0,
          },
      ]
    })),
  ],
  defaults: {
    transition: {
      name: "dummy",
    },
  },
});

• I have tried with the newest version of editly: npm i -g editly or npm i editly@latest
• I have tried ffmpeg newest stable version
• I have searched for existing issues

Start from the editly configuration in issue #149 and trace how audioFilePath, keepSourceAudio, and each clip's mixVolume are handled. Check the audio-mixing path and its existing tests or fixtures, then verify that background audio is reduced while clips marked as requiring audio are audible and that other clips retain the background track.