Seeing Multiple Outboxes in Web and ZD.

Hello all... I am having a strange issue with Zimbra Ver 8.0.1. When I log into a mailbox I am seeing multiple outboxes with what look like GUID's attached.
Screenshot is attached. I can delete them without an issue, but they just come back again a few days later. If i do nothing with them the list just continues to grow.
This is occurring in both the web interface and Zimbra Desktop so it appears to be something server-side. Any ideas what could be causing this?

Thanks!