Warm spare backup/restore never completes on primary

Backup/restore in a warm spare configuration with options shown in the attached image.

The backup, transfer, and restore all complete. The restore on the warm spare shows in the backup.log:

[2021-07-28 02:48:41] [fd682bbc-a9e4-4abc-a18e-ca8c72773d9c.INFO]: Apache will Restart now... And your GUI may die if the ports are changed !!!! [] []
[2021-07-28 02:49:41] [fd682bbc-a9e4-4abc-a18e-ca8c72773d9c.INFO]: Skipped Post Restore Hooks.. [] []
[2021-07-28 02:49:41] [fd682bbc-a9e4-4abc-a18e-ca8c72773d9c.INFO]: Running Post Restore Hooks DONE [] []
[2021-07-28 02:49:41] [fd682bbc-a9e4-4abc-a18e-ca8c72773d9c.INFO]: Finished [] []

On the primary, the last lines of the backup log:

[2021-07-28 02:34:04] [710afa24-aa33-4c34-8d33-510447ee5f93.INFO]: Finished created backup file: 20210728-023003-1627457403-15.0.17.37-48160579.tar.gz [] []
[2021-07-28 02:34:04] [710afa24-aa33-4c34-8d33-510447ee5f93.DEBUG]: Removing Warm-spare/20210727-213004-1627439404-15.0.17.37-1878693443.tar.gz [] []
[2021-07-28 02:34:04] [710afa24-aa33-4c34-8d33-510447ee5f93.INFO]: Saving to selected Filestore locations [] []
[2021-07-28 02:35:49] [710afa24-aa33-4c34-8d33-510447ee5f93.DEBUG]: Saving to: SSH:'Warm Spare' instance ,File location: /var/spool/asterisk/backup//Warm-spare/20210728-023003-1627457403-15.0.17.37-48160579.tar.gz [] []
[2021-07-28 02:35:49] [710afa24-aa33-4c34-8d33-510447ee5f93.INFO]: Finished Saving to selected Filestore locations [] []

It looks like the process is complete, but the command is still alive on the primary and never completes. I have to kill it.

1. ps ax | grep backup
   4482 ? Ss 0:00 /bin/sh -c /usr/sbin/fwconsole backup --backup=2138a950-065e-4054-8e4e-ed07ecd88c86 --warmspare > /dev/null 2>&1
   4489 ? S 4:23 php /usr/sbin/fwconsole backup --backup=2138a950-065e-4054-8e4e-ed07ecd88c86 --warmspare

This is only on the primary server. The spare server completes its restore process successfully and exits.