problem in recipe

Following some advice/examples I had this recipe in
my rc.local.s10:

 :0 BH
 * ^Subject:
 | formail -i "Subject: [Empty Subject Line]" \
   | (/usr/bin/cat; /usr/bin/cat $INFO/reject.nosubj $tmprequest) \
   | $SENDMAIL -t

However this cause infinite loops in processing a posted mail.
The log file shows many such lines:
........................
__________
>From foo@bar  Wed Feb 26 12:10:58 2003
  Folder:  formail -R"From X-From_:" -iDate: -iReturn-Receipt-To:
-iRea 2463329
__________
>From foo@bar  Wed Feb 26 12:11:08 2003
  Folder:  formail -R"From X-From_:" -iDate: -iReturn-Receipt-To:
-iRea 2492132
__________
.........................
__________
 Subject: [Empty Subject Line]
  Folder:  formail -i "Subject: [Empty Subject Line]" \   |
(/usr/bin/c 5701200
To: list@mydomain
From: [email protected]
__________
 Subject: [Empty Subject Line]
  Folder:  formail -i "Subject: [Empty Subject Line]" \   |
(/usr/bin/c 11403052
To: list@mydomain       
From: [email protected] 
__________


When I took out this recipe, loop disappears and list function
return to normal.  Any idea something is wrong?

Thanks in advance!

Zhiliang