Michael sent me a copy of the original message as it was in his mailbox, and I
now understand what happened: probably because  of the SP5 spool bug DEARN was
experiencing, MAILER  had sent a piece  of mail to LISTSERV  with headers from
one of my  messages (possibly something left over from  the last mail, without
an appropriate SPOOL cuu PURGE), and a complete BSMTP header + RFC822 header +
body from another message which shouldn't  have gone there at all. One mistery
solved :-)
 
I also wish that V2 still had VMC and VMB. The former for performance, and the
latter for compatibility with those RSCS emulators which rely on VMB. Besides,
VMB is  much more efficient than  NJE (eg it can  mix messages and files  in a
given buffer), but that's another problem. Nevermind.
 
  Eric