Hello Pat,
If the audio interface was using the wrong sample rate (48 kHz vs. 96 kHz or vice-versa) then the pitch would be out by one octave. That might happen if you'd accidentally changed the sample rate on your audio interface, or in Hauptwerk, and if the audio interface doesn't automatically change sample rate to the value specified in Hauptwerk, for example. Likewise if some other application was running simultaneously and trying to play audio through the audio interface, causing it to change sample rate from the intended value.