When an e-mail message is sent directly to an MTA such as Microsoft Exchange Server, the dot-stuffing works as expected. However, when an e-mail message goes through a Symantec Messaging Gateway appliance (formerly known as Symantec Brightmail Gateway) version 8.0.3 and above and is held either inside the Spam Quarantine or the Quarantine Incident folders and then is released to be delivered normally, the SMTP dot-stuffing does not work correctly. In other words, the incoming message before it gets received by the SMG and the message delivered to end users after it is released from the Quarantine folders are different.
There are no errors for this issue.
When SMTP dot-stuffing does not work, it is usually due to an MTA implementation not being RFC compliant. For example, JavaMail MTA, among some others, is known not to be fully compliant with dot-stuffing.
Symantec is researching this issue and this article will be updated when more information is available. There is no need to open a Support case for this issue.
More information on dot-stuffing, according to the RFC2821 ( http://tools.ietf.org/html/rfc2821#section-4.5.2 ):
Without some provision for data transparency, the character sequence "<CRLF>.<CRLF>" ends the mail text and cannot be sent by the user. In general, users are not aware of such "forbidden" sequences. To allow all user composed text to be transmitted transparently, the following procedures are used: