Post Upgrade Address Book Sync

I recently upgraded an older server and the Overview screen told me to run occ dav:sync-system-addressbook. I started running this and it’s been over 24 hours running. I don’t understand what it’s doing. This is a test server and the database table oc_users only contains 11 users so I’m unsure what this is processing.

I did lose connectivity to the server while running it the first time so I started it in a screen session so if I did get disconnected again it wouldn’t stop. However it’s been running for well over 24 hours now and the number keeps going up but it never seem to finish:

sudo -u www-data php /var/www/nextcloud/occ dav:sync-system-addressbook
Syncing users ...
 138011 [-------------->-------------]

Of note, I do see lots of activity in the redis monitor so something is happening, not sure what though.