We noticed some elog email messages were not showing up in our inboxes at random.  What we believe is happening is when a elog entry is created it is assigned a message id that the mail servers will use.  If a message is edited that same message id is used and some mail servers involved will ignore the duplicate message id.  We have also noticed when a elog entry is deleted the next entry created will assume the deleted entry message id and just like above the email will be ignored since it has a duplicate message id.