EVP88 & Sculpture patches suddenly become staccato

Anyone else have their EVP88 and Sculpture instruments go stacccato or full "plam-muted" sounding on patch change? This only seems to happen to these two instruments and there's no apprent rhyme or reason regarding the controllers I'm using. Seems completely random -- about a 1 in 20 chance. If I reload the instrument settings from the preset it's back to normal, although not if I change to another MS patch and back, which is weird since I though MS patches set up instrument and effects parameters per patch.

Not the best thing to happen mid-perfomance. Anyone else have this happen or know what it is?

This is with the latest Mainstage and Logic Studio patches and OS X 10.6.7, 8GB RAM, 750GB HD, BTW.