It could be your Bios mod. I'm running v11.5 with the Adrenaline v18.3.4 drivers on two rigs and it's very stable with zero incorrect or invalid shares. I even increased my overclock on my ASRock H110 Pro BTC+ RX 480/580 13 card rig and got an extra 8 MH/s. On the 6 card Biostar TB85 rig I got an extra 4 MH/s.
I'm using the Polaris Bios Editor 'One Click Timing Patch' for all my cards. The only change to the PBE bundled performance timings I made was replace the Samsung UberMix v3.1 timing, which is too aggresive with this one that is much more stable.
https://github.com/jaschaknack/PolarisBiosEditor
https://image.ibb.co/bDKcen/ASRock_H110_RX_580_s.png
-ethi 8
-cclock 1200,1150,1200,1200,1200,1200,1200,1200,1200,1200,1200,1200,1200
-mclock 2050,2100,2100,2250,2150,2150,2150,2250,2225,2250,2150,2250,2100
-powlim -10,-5,-10,-15,-10,-15,-10,-10,-10,-10,-10,-10,-10
-cvddc 950,950,950,850,900,850,850,900,900,900,850,900,900
-mvddc 950,950,950,850,900,850,850,900,900,900,850,900,900
https://image.ibb.co/fwYaX7/Biostar_TB85_RX_570_s.png
-ethi 8
-cclock 1150,1150,1200,1150,1200,1200
-mclock 2075,2000,2075,2075,2075,1950
-powlim -17,-10,-10,-15,-15,-15
-cvddc 925,925,925,925,900,925
-mvddc 925,925,925,925,900,925
i can see that you are doing eth only. try dual, especially keccak. besides, your timeframe is not well enough.
i can see that you have high voltages as well. 130w is too much for eth only.
regarding ethi, i heard intensity in new versions has been increased. i dont know if setting ethi 8 would lower it thus making yours stable. but i guess thats the default value.