Hi
I recently found an issue with the filters that I have subscribed myself to.
Filter using:

This return 29 items if I search it using the above filter.
But if I add a subscription to the filter it return inconsistent results sometimes I would get 1 item and sometimes 3 items via the email.

I have tried different filters as well same thing happened again. e.g. I was expecting 184 items but get 168 via email when I subscribe to the filter.
Most people would not see the problem because they wouldn't check the filter in jira again to make sure that the items they received via email matches the item you have in jira. I have also checked in case it was returning a different filter but that's not the case.
Not sure if anyone else has seen this issue before? I would appreciate any feedback.
JIRA instance details:
JIRA standalone Server version 8.02, only using jira core.