2020.10.02:06:21:50.064: main Eth speed: 209.765 MH/s, shares: 5/0/0, time: 0:01
2020.10.02:06:21:50.064: main GPUs: 1: 0.922 MH/s (0) 2: 30.010 MH/s (2) 3: 29.380 MH/s (1) 4: 30.025 MH/s (0) 5: 30.038 MH/s (1) 6: 29.923 MH/s (1) 7: 30.025 MH/s (0) 8: 29.442 MH/s (0)
I had this issue before where the main GPU0 (one in the x16 3.0 slot) would run into issues while the other GPUs always worked. This was with Claymore however but I think your reason might be similar.
After much investigating I discovered that if you have a GPU inside the main slot, it requires SLIGHTLY more power than any of the other GPUs. Usually it runs on PCI 3.0 instead of PCI 2.0 as the other 1x slot. So since it requires more power and all your GPUs are undervolted the same, the rest will hash fine but that one will crash from time to time.
My advice, just up the voltage a little and see if the problem goes away.