in this case, I have a trigger that sends out an email including the item.lastvalue, the problem is that the item is set as "text", so it's limited to 65535 chars, no problem here, the problem arises when that item generates and event and a trigger fires, making an action take place, the action is to send an email with some informative text, the alert is then stored by Zabbix into the alerts table, along with the full message sent by the action, and here's the problem, the "item.lastvalue" + the action text is bigger than 65535 chars, thus generating a MySQL error while zabbix tries to insert the alert entry, since that column is also defined as "text".

Attacched a txt with the full error from zabbix_server.log