New member here, who has just noticed this issue.
I am getting no sound on each 12th note.
Hmm, after changing sounds some more, from problems with the Matrix, to then trying the Jupiter 8V - that seemed to knock everything offline. No sound at all, just some 'pops' when changing presets.
Closed and restarted the software (Mac OS Yosemite) and took it slowly, went to the 'Studio' view, selected the Matrix. Let it load in the first preset and took a pause, then selected another preset, and it is working fine.