Although super minor, mine dropped from 13.65Th to 13.49Th average for the last block reward.  I had 3 drops in 2 shifts (I accidentally rebooted the wrong miner once but not sure of the other drops were).  In any case you would not think that 3 five minute outages would drop it that much.  The lowest my hash has been since I started was 13.57Th.  Not a biggy, but may help your investigation Kano.