Email notifications not arriving is address of sender and address of recipient are the same, even if usernames are different.

I have some projects where I have a pseudo-user called "Unassigned" (e.g. username is "unassigned_proj1"). I prefer this to the generic Unassigned feature in JIRA because, among other reasons, it allows me to specify a different e-mail address to receive notifications in each project.
For some project,s the email address associated with the unassigned user is also my e-mail address. So, if I create an issue and assign it to "Unassigned", I should, and used to, get an e-mail notification about the new issue. Since the recipient user is not my user ID, the flag for "Email me when I make changes" should not be relevant.
This has always worked fine for me, but I noticed today that I am no longer receiving email notifications when I create issues. It is possible this has only started since I installed version 3.3.3 (from 3.2.3).
After creating the issue, I checked the mail queue, and indeed it is there. After the mail queue has been flushed, I do not receive a notification.
I then changed my preference for "Email me when I make changes" to Yes, and I did receive the e-mail, so clearly this is playing a role.
Do you think there's been some improvement where JIRA decides not to send an e-mail because the originator's email address is the same as the recipient's, even if the usernames are different?
If so, that is a problem for us. We rely on email notifications in this way. I could not find any issue for such a change in 3.3 release notes.