ReportToOriginator AD attribute & Blank Return Path?

Recently got an issue sending an encrypted message with MS Online services through Forefront Protection.
The message was sent unencrypted with a error similar to the following:

Return-Path:<<.............................................>>>>Blank-Return-Path.
Then I brought it to attention of a tier above me and they referenced a attribute
ReportToOriginator value in ad/exchange?

Anybody seen this value, what it does, error or have any ideas? Thanks!