Monitoring configurations are followings.

Item configuration:

• Description: Log of $1
• Key: log[/tmp/test.log]
• Type: Zabbix Agent (Active)
• Type of information: Log

Trigger configuration:

• Descriptopn: Error log
• Expression: {Zabbix Server:log[/tmp/test.log].str(error)}

  =1

• Event generation: Normal + Multiple TRUE events

Action configuration:

• Name: alert mail
• Event source: Trigger
• Enable escalations: Uncheck
• Default subject/message: Default
• Recovery message: Check
• Recovery subject/message: default
• Action conditions: Trigger value = PROBLEM
• Action operations: Send message to User "Admin"

I added following lines to /tmp/test.log, but messages do not sent. (screenshot 1-1, 1-2)

----------
warning
error
error
error
warning
warning
error
warning
----------

It seems that the cause of this problem is handling of inserting event to escalation table and escalator process.
I created the patch for this problem, and added the same lines to /tmp/test.log. (screenshot 2-1, 2-2)
Then, I tested uncheck "Recovery message" case. (screenshot 3-1, 3-2)

I would appreciate it if you could review this patch and fix this problem!