Strange behavior of JIRA Advanced Mail Handler

Some strange behavior of JIRA Advanced Mail Handler.

I migrated old JIRA to new instance. Then set up settings. There are exist Pop services on several projects in the JIRA services. They create issues from emails for existing projects. It was an introduction.

Now i talk about error.
All Pop services have the bulk parameter set to "forward". Forwarding email is set. But it turn out, that forwarding email accaunt was disabled or deleted. So, MS Exchange returned email to the sender. Sender is a JIRA Pop service for some existing project. This service got rejected message and processed it. Service tried to create issue. Then tried to forward message to forwarding email. Exchange rejected the message again. So, after 1 day we bacome 22 thousands sendings of email. Admin mailbox was overfilled.

I think, JIRA Advanced Mail Handler should not get rejected email. Especially it should not try to process rejected messages.