Hmmm, I didn’t know that a lot of other music-apps have problems with iOS 6 as well. Would be kind if you could post some examples here, thanks!
However, I think it’s kind of obvious now:
iC Pro’s 1.0.3-Update is NOT fully compatible with iOS 5.x.
I’m not amused, since iC’s project overview was very handy indeed! 
I really hope Steinberg is not giving up iOS 5.x-Support for iC Pro anytime soon!? 