I'm currently experiencing a problem on several accounts on the same server. It seems that the mailing lists sections of Cpanel keeps sending out emails that don't exist.
For example, I have one of my sites set up with a moderated mailing list. When an email comes in, I get an email telling me that I have something waiting to be approved. Well, I got about 100 in 2 days and there's nothing there to be approved. Actually it's the SAME message over and over.
I have several clients with the same issues where the mailing lists keeps sending out old emails but the same ones over and over.