I ran into a similar problem with my current saison using the 565. It seemed to ferment heavily for 2 days and stopped dead. The other bucket (I split a 12gal batch into two fermenter and pitched both with the same starter) is going like crazy.
Despite the fact that I clearly didn't kill the yeast, I opened up the bucket and checked gravity -> it's down from 1.068 to 1.02 already. Very odd.