as per of understanding CPI only alarm can trigger an email notification, is that correct?
yes correct, that is how it should work.
in version 3.1.3 i was hit at the same bug as you describing.
https://bst.cloudapps.cisco.com/bugsearch/bug/CSCva46372
but for me there disapperet after i update to 3.1.4
if i used the application search, i could find the alarm in the system even thouge they didnt show in alarm and event.
only alarm should be able to make email notification :)