Super-simple recipie fails

This is a nearly minimal demonstration of the problem, for which I've been 
seeking help today.  Here is my rc file in all it's splendor :

        VERBOSE=ON
        MAILDIR=$HOME/mail
        LOGFILE=$MAILDIR/log
        LOGABSTRACT=NO

        :0
        * ^Subject:.*gimmie
        * ! ^Subject:.*Re:
        | /bin/echo "Take that." > $HOME/gift

If I send mail with subject 'gimmie' to myself at "user", I get the 
intended 'gift' file in my home directory.  

If instead I send the same mail to myself at "user(_at_)FQDN", I get no file.

The verbose logs are identical in each case: each indicates a match, sets 
the LASTFOLDER, execs the pipe, and notifies COMSAT (not relevant here).
Apparently procmail thinks the pipe went ok, but it didn't in the second 
case, which is obviously the case that matters.

FWIW:   "user" = kbf
        "FQDN" = phy.duke.edu
        procmail version 3.10 compiled cleanly on
        uname -a --> SunOS bigbang 4.1.3 3 sun4m

Please tell me I'm doing something silly.

Stumped,
Kyle Ferrio