inconsistent recipie failure

I *don't* understand this!  More importantly, I don't have any idea as
to how to 'fix' the problem.  Suggestions *DESPERATELY* sought.



Environment:
  O/S is FreeBSD 7.2/i386

  MTA is "sendmail" 8.14.4
  procmail installed as the system local delivery agent.

  Both are built directly from the source tarballs.


Relevant ~/.procmailrc fragments

  MAILDOMAIN="r-bonomi[.]com"
  MAILHOST="mail[.]${MAILDOMAIN}"
  VERBOSE=yes

  :0
  * <<a pattern that matches>>
  {
    :0 w
    * $ ^Received: from [^ ]* \( *[^[].*${MAILHOST}
    DELIVERABLE=|/bin/echo /home/bonomi/{{filename}}

    :0 wE
    * <<mumble>>
    DELIVERABLE=|/bin/echo /home/bomomi/{{a different filename}}
    .
    .
    .

  }

  :0 
  * DELIVERABLE ?? /home/bonomi
  {
     .
     .
     .
  }


*MOST* of the time, this particular recipie works just fine.  And I have
_dozens_ of other recipies with  the
    "DELIVERABLE=|echo /home/bonomi/{{filename}}"
action that have never (yet, anyway <wry grin>) failed. The procmail logfile
usually shows:

  procmail: Match on "^Received: from [^ ]* \( *[^[].*{{expanded $MAILHOST}
  procmail: Assigning "DELIVERABLE="
  procmail: Executing "/bin/echo,/home/bonomi/{{filename}}"
  procmail: Match on "/home/bonomi" 

Every once-in-a-while, for no reason that I can ascertain, and with no
apparent commonality in the messages involved, the following happens:

  procmail: Match on "^Received: from [^ ]* \( *[^[].*{{expanded $MAILHOST}
  procmail: Assigning "DELIVERABLE="
  procmail: Executing "/bin/echo,/home/bonomi/{{filename}}"
  procmail: Error while writing to "/bin/echo"
  procmail: Rescue of unfiltered data succeeded
  procmail: No match on "/home/bonomi" 

color me baffled, befuddled, bemused, bewildered ....

Does _anybody_ have any idea what might be going on, and how to fix it??


-- 
Robert Bonomi