My guess is that since, for some reason:
Arpeggio Mode (the only place where you can choose to turn it on or off on the Jupiter8v2) is not implimented as a MIDI-modulatable parameter
Ableton Live and Apple Mainstage have NO WAY of addressing it, when recalling a patch.
In Mainstage, you can see a list of all of the Parameters that can be mapped on to a Controller Number, so that it can be linked to a control source. The ARPEGGIATOR is nowhere on that list. Too bad, because there do seem to be a lot of extra things that aren't really needed "Parameter 12, e.g.)
Maybe this was an oversight. The Arpeggiator is such a great feature on the Jupiter 8v2, I'm sure that our Arturia Masters wouldn't deprive us of its access on purpose...