Client shows null Sender & date

[John Hendrich]

I'm using Postfix and Dovecot 2.0.19 and Virtual domains & users
(mysql).  Incoming mail is handled by Postfix and then handed off to
Dovecot LMTP for delivery.  However, the Sender and Date are essentially
null when viewing the email with either the POP3 or IMAP client.  The
logs (below) show this.  I changed the sender and recipient addresses
for privacy.

Jan 23 08:41:48 klsrv postfix/smtpd[10836]: 1F907F00276:
client=unknown[10.0.0.19]
Jan 23 08:42:07 klsrv postfix/cleanup[10842]: 1F907F00276: message-id=<>
Jan 23 08:42:07 klsrv postfix/qmgr[4889]: 1F907F00276:
from=<sender at example.com>, size=217, nrcpt=1 (queue active)
Jan 23 08:42:07 klsrv dovecot: lmtp(10845): Connect from local
Jan 23 08:42:07 klsrv dovecot: lmtp(10845, recipient at example.net):
wvU2Gq9PwlRdKgAAjuDoqw: subject=test to client: from=:
msgid=unspecified: status=saved mail to INBOX:
Jan 23 08:42:07 klsrv postfix/lmtp[10844]: 1F907F00276:
to=<recipient at example.net>,
relay=klsrv.airhop.net[private/dovecot-lmtp], delay=28,
delays=28/0.01/0.01/0.01, dsn=2.0.0, status=sent (250 2.0.0
<recipient at example.net> wvU2Gq9PwlRdKgAAjuDoqw Saved)
Jan 23 08:42:07 klsrv dovecot: lmtp(10845): Disconnect from local:
Client quit (in reset)
Jan 23 08:42:07 klsrv postfix/qmgr[4889]: 1F907F00276: removed

You can see that Postfix accepts the incoming mail (from
sender at example.com) and then the message is handed to Dovecot LMTP.  But
the from=: should be "from=sender at example.com:".

Postfix / qmgr has the sender listed (from=<sender at example.com>) but no
sender (from=) is seen in LMTP log output.  My LMTP is setup to use UNIX
sockets, not the INET socket.

Any help is appreciated.