Add the option to journal emails in a non-enveloped format.
Dave Jones commented
Journalling with a BCC to the original email will cause mail routing problems. We are experiencing mail loops using an external spam filter and smarthost outbound to it as well. The BCC addition to the original email is routing the mail back to our smarthost no matter what we do. The solution is to split a copy to the journal address and leave the original email alone so it can deliver correctly.