Yes, its not good, but for me its only started happening since I put on the new CCC and 10.12 drivers, before then I hadn't had an issue with dodgey clock dropping since essentially first month of the 58xx release.
One option is to use gpu clock tool from AMD(though from techpowerup website), it will pretty much disabled powerplay to any overclock.
THough I haven't used it in a while as MSI afterburner has been fine, you can't IIRC adjust the voltage properly. I would just set the stock 3d speeds at boot with gpu clock tool, if that disables powerplay, I'm not sure if then overclocking with MSI would re-enable powerplay or not.
The other thing used to be that MSI if you overclocked beyond the default CCC limits, would also disable powerplay till you put it down to a clock within the limits.
AT a guess its afterburner needing a slight tweak with either the new CCC, or driver or combo of both. Looks like MSI are likely focusing on new card support though so not sure if theres a fix.
TO me it seems like profiles have been changed as I can't see a way to make a profile with overdrive settings then go and alter it like you previously could, so quite possible MSI needs a "fix" to over ride CCC settings.
Problem would appear to be for me at least since I've had the 5850(launch) that CCC seems to ignore anything outside the CCC limits, now maybe its still taking control at any clock speed and Afterburner needs an update to "take control" back over the clock speeds.