why argus is sending 2 notifications by E-mail for the same event?

[Rionel.J Jeudy]

Argus sends 2 notifications E-mail for certain nodes, when the
specific node change state.
These notifications are random, which means sometimes it sends one
E-mail and sometimes 2  mails.
What could be the cause?

Here are some info i retrieve from syslog:
Jun  4 13:37:16 ARGUS-NET-MON insmod:
/lib/modules/2.4.29/kernel/drivers/hotplug/pciehp.o.gz: insmod pciehp
failed

Part of my proccesses:

oot       675  0.0  1.0  9768 8220 ?        Ss   Jun04   0:00 Argus
nobody     704  0.0  0.2  3884 1944 ?        S    Jun04   0:00 /usr/sbin/httpd
nobody     705  0.0  0.2  3884 1944 ?        S    Jun04   0:00 /usr/sbin/httpd
nobody     706  0.0  0.2  3884 1944 ?        S    Jun04   0:00 /usr/sbin/httpd
root     13743  0.0  0.2  5848 2076 ?        Ss   Jun05   0:00 sshd: root at pts/1
root     13749  0.0  0.2  2740 1644 pts/1    Ss+  Jun05   0:00 -bash
root     27918  0.8  3.4 28532 27084 ?       S    Jun05  12:58 Argus
root     29957  0.0  0.0  1452  552 ?        S    14:29   0:00
/usr/local/sbin/fping -r 3 -t 500 -e
root     29958  0.0  0.0  1444  532 ?        R    14:29   0:00
/usr/local/sbin/fping -r 3 -t 500 -e
root     29959  1.0  0.0  1444  528 ?        S    14:29   0:00
/usr/local/sbin/fping -r 3 -t 500 -e
root     29960  0.0  0.1  2408  844 pts/0    R+   14:29   0:00 ps aux