Final Cut Pro Voice Isolation Issues with External Speakers

Hey all,

Last night my FCPX audio playback became distorted when hooked up to my external speakers via a USB audio amp.

This is very similar to this situation: Final Cut Pro Voice Isolation Troubleshoo… - Apple Community

Nothing has changed with my setup in the past 6 months. I'm at a loss. I've reinstalled, cleared preferences and can easily recreate the issue. If I play the audio back through the laptop speakers it is not distorted.

Steps:

1. Import video
2. Add to project
3. Add voice isolation with auto loudness (40%)
4. Playback using the timeline the audio is distorted
5. Export the video and the audio is not distorted

I even checked a video that I released earlier this week. Everything was fine with it during editing. Now if I open the project, every clip with Voice Isolation is distorted.

Any tips would be greatly appreciated (I can disable voice isolation and it plays back undistorted).

Thanks!