Errors missing after upgrade and reboot

I had some errors in my pool, as reported here: How do I determine if the device needs to be replaced

I took some time to apt upgrade && reboot now while awaiting an answer.

Today I decided to go ahead and replace the failing disk, and the errors is gone:

$ zpool status
  pool: bigdata
 state: ONLINE
status: Some supported and requested features are not enabled on the pool.
	The pool can still be used, but some features are unavailable.
action: Enable all features using 'zpool upgrade'. Once this is done,
	the pool may no longer be accessible by software that does not support
	the features. See zpool-features(7) for details.
  scan: scrub repaired 0B in 10:34:20 with 0 errors on Sun Sep 10 10:58:21 2023

	NAME                        STATE     READ WRITE CKSUM
	bigdata                     ONLINE       0     0     0
	  raidz2-0                  ONLINE       0     0     0
	    wwn-0x5000cca099cf2fb7  ONLINE       0     0     0
	    sdh                     ONLINE       0     0     0
	    sdb                     ONLINE       0     0     0
	    sdi                     ONLINE       0     0     0
	    sdf                     ONLINE       0     0     0
	    sda                     ONLINE       0     0     0
	    sde                     ONLINE       0     0     0
	    wwn-0x5000cca252e69d40  ONLINE       0     0     0 <- this had errors
	    sdk                     ONLINE       0     0     0
	    sdd                     ONLINE       0     0     0
	    sdc                     ONLINE       0     0     0

Just to be sure, I grepped my fish history, and I never zpool cleared.

Are scrub errors usually lost across reboots? Or is this due to the upgrade?

I am confuesed.

Due to the upgrade. Error counts absolutely do persist across reboots.