Persistent ZFS pool errors on Ubuntu, even after repeated scrubs

Question

My 3-disk ZFS pool has been scrubbed several times after replacing failing disks.

"zpool status -v" provided a list of files which were deleted and removed a good number of errors.

Despite running a couple of "zpool scrub" processes to completion, I am still getting output as follows:

root@ra:/root# zpool status -v | head -25
  pool: backup
 state: ONLINE
status: One or more devices has experienced an error resulting in data
    corruption.  Applications may be affected.
action: Restore the file in question if possible.  Otherwise restore the
    entire pool from backup.
   see: https://openzfs.github.io/openzfs-docs/msg/ZFS-8000-8A
  scan: scrub canceled on Thu Jun  1 16:23:28 2023
config:

    NAME                        STATE     READ WRITE CKSUM
    backup                      ONLINE       0     0     0
      raidz1-0                  ONLINE       0     0     0
        wwn-0x50014ee2bf658d03  ONLINE       0     0 1.25K
        wwn-0x5000c500e5ee7f5b  ONLINE       0     0 1.48K
        wwn-0x5000c500e5ef7436  ONLINE       0     0 1.48K

errors: Permanent errors have been detected in the following files:

        backup:<0x2ed701>
        backup:<0x2e1d02>
        backup:<0x235104>
        backup:<0x2e1d05>
        backup:<0x2e1d06>
        backup:<0x2e1e06>

My forays into the docs have shown no way of repairing this. The pool as a whole can be seen to have zero READ/WRITE/CKSUM errors, as does the disk array. Each member of the array, however, has a significant number of CKSUM errors.

Should I be concerned? Will the pool continue to remain error free until more hardware starts to fail?

Thanks,

Paul