Only noticed with one paticular host that snmp responses are not processed to the point they are entered into the database. I noticed the issue since the graphs had "spotty" lines or information missing for random times. I am not using bulk requests. I see the packet coming into zabbix via tcpdump. I do not have debug info present on this ticket but I did increase debug level and compared all messages related to failed check with another check to the same host and seen no differences.

Checks are every 5 minutes. You can see in attached file "tcpdump.png" that packets are sent both ways for snmp check at 16:10 but no values exists in history. Graph history values in file attached "value-history.png"

I've increase debug levels but found nothing. I have also removed host and re-configured. Used bulk request and no Bulk requests. Can anyone point me to the next step?