[CentOS] Semi-OT: fail2ban issue

On a CentOS 6.7 system that's been running fail2ban for a long time, we
recently started seeing this:
ct 28 19:00:59 <servername> fail2ban.action[17561]: ERROR iptables -w -D
INPUT -p tcp --dport ssh -j f2b-SSH#012iptables -w -F f2b-SSH#012iptables
-w -X f2b-SSH -- stderr: "iptables v1.4.7: option `-w' requires an
argument\nTry `iptables -h' or 'iptables --help' for more
information.\niptables v1.4.7: option `-w' requires an argument\nTry
`iptables -h' or 'iptables --help' for more information.\niptables v1.4.7:
option `-w' requires an argument\nTry `iptables -h' or 'iptables --help'
for more information.\n"

My manager thinks it might have been due to the recent update. I, however,
am extremely confused, as in neither in the manpage, nore fail2ban --help,
do I find *ANY* reference to a -w flag.

Anyone have a clue here?

     mark