Steps to reproduce:

1. We have a trapper item prototype which gets data from a script. When item does not receive data it was set to delete with "Keep lost resources period" set to 0.
2. This item prototype has an associated trigger prototype. 
3. Starting at 3:55 PM CST there were 12788 emails sent to one user for 246 unique discovered items until 9:15 PM CST when i disabled the action to stop the emails. Refer attached snapshot of Alerter. There were thousands of OK emails as well as PROBLEM emails. 
4. Even though our Action is configured to send email every 5 mins, I could see multiple emails being sent for same item within a few seconds interval. Refer attached snapshot of action log.
5. Action log indicates multiple events were generated for same problem even though trigger has "PROBLEM event generation mode" set to single. 

6. Looks like some dead loop occurred in escalation logic. Please help us fix this problem so that it won't reoccur again. 

Result:
See screenshots
See log file 
Expected:
Emails should be sent every 5 mins. Email count should have quite less. Multiple problem events should not have been generated.