Arturia prophet plugin randomly changes preset in mainstage

Firstly thanks to everyone for your replies - glad I'm not trying to solve this on my own any more.
The sampler instrument idea would be tough in this case as I'm playing quite involved parts with a live band.

Let me give you an example of what my problem is.
I have a mainstage patch called Skin Deep Split cos the tune is called Skin Deep and I've split the keyboard. There are two channel strips in the patch, one running Arturia's Minimoog and the other running the problematic Prophet plugin. The prophet is set on a program (preset?) that i've called LowSkinDeep. Now if I send a program change message from my Nord Lead in order to change the mainstage patch then the patch changes as expected but in addition the prophet plugin on the patch that I've just come from gets changed to a different program, in this case one called 'Spindown' (named after another song). I can even watch this happening by having the prophet's editor screen open. So when I come back to my original patch (Skin Deep Split) the prophet will be playing the wrong sound even though the minimoog on the other channel strip is fine.
After this point no amount of program change messages will alter the prophet program - it stays on the same wrong one.
This happens with lots of different mainstage patches within my concert. The prophet will always change itself to the same program every time I repeat the experiment on the same patch, but interestingly for each different mainstage patch it selects a different program to use as its favourite.
I've got some of Arturia's other analogue synth plugins running in the same concert but it's only ever the prophet that behaves like this.
I have tried saving both the concert and the prophet program on the correct sound before I start changing patches but it makes no difference.
Any ideas?

Yes I'm using mainstage 2.1 though I also had exactly the same problem with Mainstage 1. I'm also having the same problem using V1 or V2 of the arturia prophet.

I'm becoming convinced that this is a bug in the prophet software.
I'm not using any aliases, always separate instances of the plugin, and yes I can get independent windows for each instance.

If I change mainstage patches with the cursor then the prophet does not change and everything works perfectly. Also if I connect a usb keyboard and make patch changes with that, then in this concert at least the prophet remains unchanged, but I have had exactly the same issue using this usb keyboard in other concerts.

It seems that the prophet is responding to program change messages, but in a way that I can't predict. For instance in one concert the prophet plugin works fine on mainstage patch 4 but on patch 5 it changes to a different sound, whereas in another concert it's the other way around, so it's not always doing something strange in response to the same midi message.

If there was a way to disable a plugin's response to program change messages within mainstage then I'm sure that would solve my problem, but I don't see anything like that so far. In the channel strip inspector there are check boxes to filter out other midi messages but not program change messages.

Being able to change the sound setting on a plugin synth from an external keyboard is something I'd really like to be able to do as it would surely be much more memory efficient than having different instances of the synth for every patch. It's frustrating that this is happening on one plugin without me being able to control or predict it.

Still no response from Arturia!