Wow. The CS-80V has been one of the more reliable soft synths I have. Are you using a Mac or PC? It could be a Mac or Ableton specific problem.
The only thing I would suggest, as a work around, is save your CS-80V preset. Then when you restart Ableton and the synth is messed up, remove the synth from the track and then load it again and choose your saved preset and it should work.