Sample Editor notes audio can't be heard or moved when using VariAudio


Two strange things have started happening with VariAudio, I think since I upgraded to CB Pro 12. I’ve created a single harmony track from the main VOX track and turned on VariAudio in the Editor window, just as I always used to do.
Firstly, I can’t manually change the pitch of any of the harmoniser track notes - up or down - as they always fly back to where they are.
Secondly, although I can solo the sample editor window to just hear that track, I can no longer hear the sample notes as I try to move them up or down. This is still happening on another piece I’m working on where the harmoniser audio can be manually adjusted - I can solo the track as a whole and hear it playing in real time, but I can’t hear the individual notes as I manually move their pitch up or down.
I am not sure these two problems are necessarily related, but I haven’t experienced either before upgrading to CB Pro 12. Coincidence?
Any thoughts on either or both would be very welcome.