UPDATE!!
This is fixed in 4.20.
From the 4.20 release notes:
- New: Added BypassVolumeScaleForPriority bool to SoundBase properties, enabling specified sounds to ignore Volume Weighting during Priority Sort.
- …
- New: Added ability to bypass volume-weighted prioritization for sound sources and only use priority.
Checking BypassVolumeScaleForPriorty in the properties window of my soundwave asset completely resolved the issue for me.
Just want to say thanks to @dan.reynolds and the rest of the team for fixing this. You guys really are the best!