MIDI CC 2 "Breath" unwantedly controls output volume

[landgrvi]

• Cardinal Main 24.05
• Carla 2.5.8
• Ubuntu Studio 24.04
• Korg nanoPAD2

Hello folks, I just got a Korg nanoPAD2 and am experimenting with the XY pad. X is CC 1 (aka Modulation Wheel) and Y is CC 2 (aka Breath Control). I load up the Host MIDI CC module, and indeed have voltages on 1 and 2 corresponding with X and Y on the pad. So far so good!

The problem is that changing Y (CC 2) also changes the overall output volume of the patch. 0V gives no volume out, and 10V gives full volume out, as if it's controlling a fader that I don't see.

This seems to affect the main version but not the synth version, and affects LV2 and VST3 versions. It doesn't seem to affect other plugins loaded in Carla.

Is there some default MIDI mapping that I can change? I've only been playing with Cardinal for a couple of weeks and am totally open to this being user error / ignorance, so if somebody can help a noob out I'd really appreciate it.

EDIT: Just tried the MIDI event generator plugin, and get the same results sending the events to Cardinal by hand, so it doesn't require the nanoPAD2 specifically.