Exim email queue doesn't show all emails in queue.

I've found that sometimes exim doesn't appear to show all the emails in the queue. You can see them in WHM > Mail Queue Manager but not on the command line without a special command. The standard command is as follows and usually works fine: /usr/sbin/exim -bp But I've found that in some rare and strange cases (example: mailman keeps trying to send to a server that is misconfigured to permanently greylist all incoming email) there are emails that stack up in the queue that the above command cannot view (even though they show up in Mail Queue Manager). The follow command works to show the emails and I don't understand why: /usr/sbin/exim -C /etc/exim.conf -bp Can anyone shed some light on this?