missing "Content-type: ... boundary" from header on a forward

I have a simple recipe to forward mails to a small list like in:

:0 c
* ^(To|Cc):.*[email protected]
* ? formail -X"From " -xFrom: -xSender: -xReply-To: -xResent-From: \
     | /var/private/.bin/multigram -b1 -m -l 28668 /my/path/sound.list.txt
{
   :0 fwh
   | formail -I "Reply-To: [email protected]"
     :0A
     !  `cat /my/path/sound.list.txt`
}

It works fine forwarding mails, except that the forwarded mails all are =

missing from their header section "Content-type: multipart" lines like:

Content-type: multipart/alternative;
 	boundary=3D"B_3487949262_366283"

and instead this is seen in the header:

Content-type: text/plain;
 	charset=3D"UTF-8"

Since the boundary info is missing the multiparts of a mail body are all =

displayed as plain text.

I am not sure what happened, or wrong with my recipe. I hope I won't have =

to come up something to capture the "Content-type: ... boundary" lines to =

insert back to the header ;-)  Any advice please?

Zhiliang