Tarsnap failing to make backups

[Michael Jung <mikej@mikej.com>]

Tarsnap 1.0.39
FreeBSD 12.0 r326073

Been using tarsnap for quite a while - I noted that backups are failing.

Example:

#/usr/local/bin/tarsnap --keyfile /root/tarsnap.key --cachedir 
/var/cache/tarsnap/ -c -f backup-`date +%Y-%m-%d` /etc /root 
/usr/local/etc /usr/local/www /private /var/mail /usr/home
tarsnap: Sequence number mismatch: Run --fsck
tarsnap: Error creating new archive
tarsnap: Error exit delayed from previous errors.
[root@firewall ~]#


If I run tarsnap --fsck it exits like this with no errors

  Archive 196/196...
Phase 5: Identifying unreferenced chunks
[root@firewall /usr/home/mikej]#

I can successfully remove archives like

#tarsnap -d -f <archive-filename>

without issue.

Lastly, there are plenty of funds in my tarsnap account and I'm not 
running low on disk space.

Any points on where to look for the problem?

Thanks!

--mikej