Yes, exactly same to me, with and without undervolting: they are much frequent when idling.
AMD Power monitor shows also frequency switching from 2100 to 1050 Mhz
If you can run my program above, fire this command:
> turionpowercontrol -pallc 6 48 1 13
In my experience it stops transitions to pstate 6 immediately just by overwriting pstate 6 vid, fid and did.
Maybe try also
> turionpowercontrol -CM
It shows to me some transitions to pstate 7 too
edit: since I don't know your processor model