I had a similar problem, Reverb volume didn’t affect to the sounds, resolved changing the sound class type of the cue’s to “Music”.
I think that “Music” is not correct for voices, but it works for now.
Also some sounds are stoped when the player goes far, with some class type. With music class no, there are two pawns talking, you goes far, and when return, the pawns continue talking. I need to investigate some more.