VERIFIED SOLUTION i
Sending an email to a Mailbox which is full, EngageOne Digital Delivery not able to identify delivery failure notification as bounced.
It is a product defect where for each outbound email, EngageOne Digital Delivery sends a header with name X-references and expect this header in bounce email (inbound) to successfully update the status of outbound message (for example bounce or 'out of office'). If this header is missing in the inbound bounce message, it will treat it as a new inbound email instead of a bounce email. There is a difference in header expected by EngageOne Digital Delivery.
ResolutionUPDATED: March 6, 2018
It has been fixed in the EngageOne Digital Delivery Version 2.4.X