We sent out a pre-event bulk email to all event attendees on Nov 3. Today, we were informed by someone who just received their email today (Nov 30 - I can confirm in her message header that it arrived to her mailbox Nov 30, it wasn't that she just didn't see it until today). The Mailing Report lists that the mailing was successfully delivered to all 175 recipients, and that the start date was Nov 3, and the ending date was Nov 30.
Why in the world would it take nearly 4 weeks to complete a mailing to 175 individuals? How can we tell if it was just this one individual who didn't receive it until today? (The Activity includes the start date of the bulk email, but not the date that the activity was completed for her.)
Edited to add:
Now that I can find the reports, I see that the entire list didn't receive the mailing until yesterday.
Looking into the job scheduling and logging, I discovered that the job has been starting as scheduled every 15 minutes. However, the job log does not show that the job has finished executing until the time stamp that the mailing actually went out yesterday. SO... would this have been a problem with the server rather than with civi? Is there a way to get warning notices if a mailing hasn't completed within a certain amount of time so this doesn't surprise me (or less technically minded colleagues) later?
In an exchange with my hosting support (civihosting.com), we've decided that since it is working now, we won't pursue it to determine the reason. Kudos to anyone who can think of more information, though.