Just tested that AFG,
Phones on mainslider up and down; back to main out slider, up and down; jumped different banks and then back to layer 4 re-did slider;

No issues. Certainly NO modulation of any sort.

The only thing I noticed is some "slight" digital artefacts as you moved the slider up or down too quickly whilst having an audible sound, but this is normal for a digital output.

Dennis