I’ve been suuuuper lazy troubleshooting this so it’s been a few weeks, but I talked to WD support, they said to run a full extended S.M.A.R.T. test on the drive, it passed with no issues.

Reconnected it to my server using a different SATA cable on a different port on the motherboard, with a different power connector. It resilvered with no problems, and a zpool scrub returned no errors this time so hopefully I’m in the clear!

I have a script that runs once a week that does a scrub then sends the output of zpool status to a Discord channel. When this first started it had read errors (as mentioned in the post), then checksum errors two weeks later. With there being a couple different errors before troubleshooting, and now with no errors after a scrub I’m hoping this means everything’s fine now.