Look at this line
Chain[8] Chip[1] TempTypeID=41 middle offset=37
Chain[8] Chip[1] local Temp=66
Chain[8] Chip[1] middle Temp=93
Special fix Chain[8] Chip[1] middle Temp = 81
Done read temp on Chain[8]
do read temp on Chain[10]
Chain[10] Chip[1] TempTypeID=41 middle offset=33
Chain[10] Chip[1] local Temp=67
Chain[10] Chip[1] middle Temp=80
Special fix Chain[10] Chip[1] middle Temp = 82
Done read temp on Chain[10]
It looks like it reach the high temp protection that is why your miners hashrate is down or stop you must add more cooling devices in your room or you can try to change the fan speed to maximum speed.
You can follow the guide here
https://bitcointalk.org/index.php?topic=2690140.0 but first do a reset it to factory default here's the guide
https://enforum.bitmain.com/bbs/topics/3957Let me know if it's still persist.