All triggers with nodata functions change to ON after a server is running anywhere from 1 to 7 days. It use to be a weekly problem, but is now a daily issue with our server. After closer inspection, this happens because the Zabbix server stops recording ALL items. I checked 3 servers, and they all stop collecting information at the same time, thus causing the working portion of zabbix to trigger alerts.

One thing to note is that simple checks like icmpping still collect data when this issue occurs.

After the above happens the zabbix server continues to run, except the nodata triggers are ON and no data related to agents is being collected by the server.