OT? Help identify source of this error message.

[John Allen]

I am getting the following error message in my mail log:
Sep 15 22:22:17 bilbo postfix/smtpd[2319]: warning: Illegal address 
syntax from localhost.lan[127.0.0.1] in RCPT command: 
<postmaster@!change-mydomain-variable!.example.com>

I think it is coming from spamassassin, but I cannot find it in any of 
the various spamassassin files.

TIA
John A