Lopsided disk usage in RAID 1

I have a R250 server running Windows server 2022, with a PERC H355 raid controller. I have two identical 1TB drives configured RAID 1 (mirrored).

When I look at the usage LEDs on the drives, drive 0 blinks ~ 10X more than drive 1. Why is this? Note that this is rather recent, and when first used the two drives blinked at the same rate.

iDRAC shows no problems with storage. Booting into the BIOS, both physical drives pass the self test.

iDRAC Storage/VirtualDisks/CheckConsistency both drives blink the same. This will take hours, so I'll reply to this post with the result.