It was around 62-65C when I found miner. If it was getting into the 70C range I would have backed frequency back down.

Part of me wishes to believe that it is a thermal issue with temperatures running 42C and 43C at 200M, however when frequency is at 250M-300M temperatures are right at 50C with numerous HW issues.
That makes me think something else is wrong.

I can tolerate it hashing at 650GH/S with lower power consumption, but it is definitely not preferred.
I guess next question is does checking thermal paste void warranty (if not already voided) and any other thoughts as to what to check besides thermal paste.