I received the following bug report from our distributor:
"Using the Artist Control controller to adjust parameters, continuous parameters are set to minimum value once the respective knob is touched, and remain minimum regardless of the knob setting.
Discrete parameters (On/Off or multi-state) are controlled fine via control surface.
Tested with Artist Control (latest firmware), EUControl 3.3, Pro Tools 12.1, OS X 10.10.4 Yosemite....
I'm not sure, but it seems that this issue is related to JUCE, as we have seen other JUCE products where this issue appears. Can you investigate if this is a known issue for JUCE and if there is anything you can do about?"
I imagine that this is due to the fact that JUCE doesn't currently support EUControl. However, parameters are definitely responding, albeit in a broken manner. It's unfortunate that this occurs with such a boutique controller, but apparently a significant enough portion of our userbase uses one.