Changing arpeggio octave range mutes channel strip

I've been trying to map a mod wheel (akai mpk49) to arpeggiator octave range for couple of hours now and it just does not work.

The mapping "looks" fine, but every time i move the mod wheel, the channel strip gets muted and even after I un-mute it manually it does not seem to have changed the octave range.

Is it possible to somehow troubleshoot/debug this strange behavior ? I have the latest versions of OSX and MainStage installed.