I've been noticing this, too.  About six of them in the last
three months, out of 200 messages. I'm not certain what LISTSERV
filters on, but I've also noticed that my own filtration system
has started missing them (filtering on every combination of "out
of /the/ office" I can think of).  LISTSERV 1.8e, here, has been
bouncing most of them to the -request address,

Is there a way to tweak LISTSERV's filtering (if I can figure
out what it's missing)?

-- Russ

St. Thomas University
http://www.StThomasU.ca/~hunt/