well, could be something in the midi stream where it is interpreting it as a command for the mixer?
When that happened to me, I was actually working on getting my Keystation Pro 88's knobs and faders to control the RME mixer - as well as have buttons and sliders in the environment control the mixer.
I'm sorry, but it was so long ago that I worked on getting mine set up. I remember having strange things happen like that, and there was a simple fix.
But, do check the mixer's menus, and see if anything has a checkmark beside it that you didn't put there.
If all else fails, you can contact
http://www.synthax.com/ in the U.S. by phone - they used to have free support, but I think they cut this down to 30 or 90 days.