Expired articles originated from nnimap group keep expiring forever

[Teemu Likonen]

I have an annoying problem with forever-expiring "nnimap" articles. I
use this kind of group settings (simplified):


    (setq
     gnus-parameters
     `(("^nnimap\\>.*"
        (spam-contents gnus-group-spam-classification-ham)
        (spam-process ((spam spam-use-bogofilter)
                       (ham spam-use-bogofilter)))
        (spam-process-destination . "nnml:spam")
        (expiry-wait . immediate)
        (expiry-target . "nnml:old")
        (display . all)
        (gnus-large-newsgroup nil))

       ("^nnml:old$"
        (total-expire . t)
        (expiry-wait . 365))))


When I expire (with E key) an article from an "nnimap" group the article
goes to "nnml:old" group (after I exit the "nnimap" group). Fine. But if
I then go to "nnml:old" (the article is there with "O" flag.) and exit
the group I see this article being expired again. The expiry target is
"nnml:old" so the article is deleted and then put back to the same
group. It's a kind of expiry loop which happens every time I enter and
exit "nnml:old". I'd really like to get rid of this.

Well, at some point the database of "nnml:old" gets somehow corrupted
and this article does not show anywhere. I fix this by going to *server*
buffer and regenerating the "nnml" server database with "g" command
(gnus-server-regenerate-server). After this operation the article
correctly shows up in "nnml:old" group and the expiry loop is gone. All
is good again.

(I daily expire articles from some "nnml" groups to "nnml:old" as well
but they don't cause this expiry loop. These groups have the same
gnus-parameters as the above "nnimap" group.)

I use Gnus version 5.13 from Debian 6.0's Emacs 23.2 package.

Thanks for any help or information.