I fixed this issue using AwesomeMiner (paid software) and created a rule to restart the miner if these 2 conditions were met:
-Lower than 13.3TH/s AVG (for 13.5 s9) and lower than 13.8TH/s AVG (for 14th S9)
-More than 500 Accepted shares (so the miner has time to warm up and reach stable avg speed, or else the software restarts the miner prematurely)