No there have been no updates to the server. This one message is the only one it occurs on that I'm aware to this point have months of operations on this version.
Of course I had already checked for updates to the server and similar problems. I came the forum as a last resort.
I do have a bit more info. The issue appears related to when amavis passes the message off to spamassasin.
zimbra amavis: SpamControl: init_child on SpamAssassin done
zimbra postfix/smtp: AF8BD4B40A3: to=<firstname.lastname@example.org>, relay=127.0.0.1[127.0.0.1]:10024, delay=48143, delays=48135/0.01/0/7.8, dsn=4.4.2, status=deferred (lost connection with 127.0.0.1[127.0.0.1] while sending end of data -- message may be sent more than once)