Me too, me too.
Mine does it as well, 2011 GSA. It seemed to start when my Anakee 2 rear got about half worn. I have 18K miles on it and need to replace the rear tire soon. It changes with lean angle so I chalk it up to tire noise and the rest of the drive train resonating. There was no hint of it with the Tourance EXPs that were the original tires.