Symantec Messaging Gateway (SMG) MTA logs report error level entries with the following message:
No other symptom or malfunction has been noticed on the product.
Message bounced due to bifurcation of too many recipients: 215 > 150(max)
2012 Sep 23 13:19:59 CEST (err) ecelerity:  [error]: SMS_AUDITLOGGER-02520: Domain container is NULL.
For this scenario to occur, two settings must match:
Verify the value for Maximum number of messages in delivery queue under Administration > Hosts > Configuration > <hostname> > SMTP > Advanced Settings > Delivery is set to the default value or well above the amount of potential recipients on any given email message.