Simon Josefsson <jas@extundo.com> writes:

> I think it was reported to happen for nnmail too.  Hm.  Those who are
> seeing this, are you using spam.el and downloading bodies too?

Using spam.el, yes.  Relevant parts of my .gnus file:

(setq nnmail-split-fancy
      '(|
        (: spam-split)
        (to "reuse-\\(\\w*\\)@mit\\.edu" "mail.lists.reuse.\\1")
        (any "dmaze@.*mit\\.edu" "mail.misc.personal")
        "mail.misc.impersonal"))
(setq nnmail-split-methods 'nnmail-split-fancy)
(setq mail-sources '((imap :server "po10.mit.edu" :password ""
                           :stream kerberos4 :authentication kerberos4
                           :predicate "UNDELETED")))
(setq spam-split-group "mail.misc.spam")

Given this set of rules, the attached message trips the bug: it got
sorted into mail.lists.reuse.ask, where reuse-ask is only mentioned in
the body of the message.  It should go in mail.lists.reuse.housing,
since that's what's in the headers.