Whenever Kill Dry is On, think of it as removing the dry signal entirely from the output of Preset A. Now, consider your Mix/Intensity/DirtLevel/Depth parameter is set to 50% or the mid point. What this means is that there is equal parts dry and wet signal in the output. However, because Kill Dry is ON all you will perceive is the wet portion of that mix. If you turn the Mix/Intensity/DirtLevel/Depth parameter completely counter clockwise (set it to zero), think of it as 100% dry signal, 0% Wet signal – or no output from the Preset. In essence, when Kill dry is ON for Preset A, the Mix/Intensity/DirtLevel/Depth control acts like a wet signal volume control.
I should be able to mix cleanly from dry A to wet A (e.g. via an expression pedal), while keeping B fully wet. With the current behaviour this is not possible. Thanks!
If this is what you want to do then Preset A should not be set with Kill Dry ON. You can just map your expression pedal to whichever Mix/Intensity/Depth parameter you prefer.