I had those errors before, but that was a while ago. I don’t recall how it was fixed—it might have been destroying and recreating the RAID. I feel like I had those errors when my UPS was having issues with quick brownouts where the power dropped for like a second or two. After I replaced the UPS with a better model, I haven’t seen that happen to me anymore, and some of my disks had a runtime of 8 years, lol. Some were newer, like 2-3 years old.
If you have power dips where the UPS takes a second to provide power to the NAS, it might be causing the errors.