"spare-X" device remains after resilvering

Hi, I have a zpool that currently looks like this (some lines elided for 
brevity; all omitted devices are online and apparently fine):

   pool: zp1
  state: DEGRADED
status: One or more devices has been taken offline by the administrator.
         Sufficient replicas exist for the pool to continue functioning 
in a
         degraded state.
action: Online the device using 'zpool online' or replace the device 
with
         'zpool replace'.
   scan: resilvered 1.76T in 1 days 00:38:14 with 0 errors on Sun Jun 19 
22:31:46 2022
config:

         NAME                       STATE     READ WRITE CKSUM
         zp1                        DEGRADED     0     0     0
           raidz2-0                 ONLINE       0     0     0
             gpt/disk0              ONLINE       0     0     0
             gpt/disk1              ONLINE       0     0     0
             ...
             gpt/disk9              ONLINE       0     0     0
           raidz2-1                 ONLINE       0     0     0
             gpt/disk10             ONLINE       0     0     0
             ...
             gpt/disk19             ONLINE       0     0     0
           raidz2-2                 ONLINE       0     0     0
             gpt/disk20             ONLINE       0     0     0
             ...
             gpt/disk29             ONLINE       0     0     0
           raidz2-3                 DEGRADED     0     0     0
             gpt/disk30             ONLINE       0     0     0
             3343132967577870793    OFFLINE      0     0     0  was 
/dev/gpt/disk31
             ...
             spare-9                DEGRADED     0     0     0
               6960108738988598438  OFFLINE      0     0     0  was 
/dev/gpt/disk39
               gpt/disk41           ONLINE       0     0     0
         spares
           16713572025248921080     INUSE     was /dev/gpt/disk41
           gpt/disk42               AVAIL
           gpt/disk43               AVAIL
           gpt/disk44               AVAIL

My question is why the "spare-9" device still exists after the 
resilvering completed. Based on past experience, my expectation was that 
it would exist for the duration of the resilvering and after that, only 
the "gpt/disk41" device would appear in the output of "zpool status."

I also expected that when the resilvering completed, the "was 
/dev/gpt/disk41" device would be removed from the list of spares.

I took the "was /dev/gpt/disk31" device offline deliberately because it 
was causing a lot of "CAM status: SCSI Status Error" errors. Next step 
for this pool is to replace that with one of the available spares but 
I'd like to get things looking a little cleaner before doing that.

I don't have much in the way of ideas here. One thought was to export 
the pool and then do "zpool import zp1 -d /dev/gpt" and see if that 
cleaned things up.

This system is running 12.2-RELEASE-p4, which I know is a little out of 
date. I'm going to update it 13.1-RELEASE soon but the more immediate 
need is to get this zpool in good shape.

Any insights or advice much appreciated. Happy to provide any further 
info that might be helpful. Thanks.