I recently bought a 73-Key SV-1.
I am having lots of fun with it, but the behaviour of my Moog EP-2 expression pedal with it is not as expected, even after calibration with the SV-1.
Basically, rather than the volume going smoothly from quiet to loud as I move it from its lowest to highest position, it is going from loud to quiet to loud.
An illustration:

I'm new to the SV-1 (and keyboards in general) - is this normal behaviour?
If not, any guesses why this happening and/or how to resolve the issue?
I suspect that I may have been slightly mis-sold the Moog pedal - perhaps it's designed this way for operation with Moog's own hardware?
In any case, any ideas or suggestions would be much appreciated.
Fortunately, other than this teething issue, I am absolutely LOVING the SV-1!