[Mimedefang] Quarantine notifications getting quarantined?

[Rich Stanton]

I'm using spamasassin 2.60, with mimedefang 2.39 on a yellow dog 3 system.
My filter is basically edited according to script 4 from here
(http://www.thompsonic.com/util/antispam/mimedefang.html).  I.e. messages
with a score greater than 5 are quarantined & bounced, with a quarantine
message generated.

In the last couple of days I've had a much greater number of quarantine
messages than normal, and on examining them I've found that most of them are
quarantine messages themselves.  These each generated a bounce to the
mimedefang user (which has no alias set up), and this 'bounce' message from
sendmail to mimedefang was also quarantined.  Finally a notice of this
failure was sent to the postmaster of the local system, and this too was
quarantined.  I've also had outgoing delivery-status messages from
FETCHMAIL-DAEMON quarantined, as well as some incoming information emails
from FETCHMAIL-DAEMON.

I've only noticed this happening in the last few days, and don't remember
changing anything in my mimedefang setup.  As a workaround I've whitelisted
everything on the local machine & set up an alias for the mimedefang user,
but I wondered if anyone has seen this or knows what might have caused it.
The only change I remember making recently was to add a dnl before the line:

FEATURE(`accept_unresolvable_domains')dnl

in my sendmail.mc, but I don't see how this could have effected anything!