Do not worry, this is a bug that has cropped up for multiple people. Some how some of Viv's voice lines got kicked to the music channel instead of the voice channel. It has been addressed and should hopefully not happen in the next patch.
I'm going to have to fiddle with the audio over all, as I did receive reports that Viv's lines tend to be a bit louder than Vio's. This time I'm going to make very, very sure that things are coded right.