[CentOS] Sudo #includedir function ignored CentOS 6

I am unable to get the #includedir function to work with sudo. This works just fine on all my CentOS 5.6 servers, but on 6 it is being ignored. I have this line in the file /etc/sudoers.d/zabbix-puppet

zabbix ALL=NOPASSWD: /var/lib/zabbix/bin/start_puppet

However sudo still requires a password. If I put that same line into /etc/sudoers file , there is no password prompt. At the end of my sudoers file I have this line

#includedir "/etc/sudoers.d"

It seems that line is being ignored.

The permissions on the file in that directory are 0440.

Any ideas would be greatly appreciated.

Thanks - Trey