Yeah, you run into common (or uncommon but repeatable) errors often that you’re either like “I know exactly how to handle this” or “I remember running into this before but just need to jog my memory real quick…”
I had a similar odd issue with my HDDs. I had 20 HDDs in my system of various ages, and they would seemingly randomly throw shit tons of R/W checksum errors and drop out of its assigned zpool. It was almost never the same drive. SMART said the drive was perfectly fine. It would happen on brand new drives I got a week ago and drives that were years old. I swapped power cables, SATA/SAS controllers (three different HBAs and 3 onboard controllers) and cables, bought a UPS, etc… and nothing seemed to work. I didn’t think it was a PSU issue since I had a 1.5 KW PSU and my Kill-A-Watt meter was only showing about 600w at full load. This took literal months of troubleshooting. Someone on Reddit finally suggested trying another PSU or limiting the amount of drives attached to the PSU. I bought a cheap 400w PSU and connected about 8 drives to that… and all the errors stopped.
It turns out that there wasn’t enough power supplied on the 5v rails to write the data without errors 100% of the time, but it had enough power supplied on the 12v rail to spin all the motors. First time in 25 years I’d ever seen that, but that was also the first time I’ve ever had like 20 drives connected to one PSU. I was literally about to throw in the towel because drives dropped out on a daily basis, but after like 2 or 3 total dropped no more usually failed.