GNUS bug: Summary line doesn't match article

[Sascha Wilde <wilde@sha-bang.de>]

Hi *,

I'm experiencing a strange and most annoying problem with gnus:

in some Newsgroups (especially those with much unread messages, but
this might just be an coincidence) while reading a thread I get
articles displayed, which are totally unrelated and certainly don't
match the active line in the summary buffer.

For an example see this "screenshot":

------------------------------------------------------------------------

   [  30: topmind                ] Re: Design Patterns and Functional
R +    [ 107: Kent M Pitman          ]
           [  40: Don Geddis             ]
  +            [  30: Kent M Pitman          ]
-111:----F1  Gnus: c.l.lisp [231816] {16467 more}   Top (2,13) (Summary
From:  Mariano Montone <marianomontone@gmail.com>
Subject: Message passing syntax
Newsgroups: comp.lang.lisp
Date: Tue, 24 Jul 2007 02:10:14 -0000
Organization: http://groups.google.com
User-Agent: G2/1.0

------------------------------------------------------------------------

The currently marked "active" article is the `R' marked article by
Kent M Pitman, but as you can see gnus really displays an article by
Mariano Montone, where not even the subject matches.

I see this phenomenon in different groups and different threads.
Sometimes only a few messages scattered other an thread are
affected, sometimes whole threads victims of this problem.

It's 100% reproducible: Once I saw the problem with one message I can
even close Emacs completely, after re-entering the group the message
in question will still be replaced on display be the same unrelated
other message.

It seems only to affect net-news, never experienced this with mail
groups.

Originally I stumbled across the problem in Emacs CVS HEAD (gnus
5.11), but I just tried ngnus.tar.gz and gnus-5.10.8 and all behave
exactly the same.  Maybe the problem is in some way or the other
"cached", so that I see it even with gnus versions, not having the
bug?  Or might it be a bug in Emacs CVS HEAD, which is triggered by
gnus in this strange fashion?

Any hints and tips and especially workarounds are highly appreciated!

I very much depend on gnus as a mail and news reader and this problem
is highly annoying and kind of alarming at the same time...

cheers
sascha
--
Sascha Wilde
... mein Opa [...]  würde an dieser Stelle zu Dir sagen: Junge, such Dir
ne Frau, bau Dir ein Haus, mach ein Kind und laß' die Finger von dem Zeug,
das Du gerade machst. -- Michael Winklhofer in d.a.e.auktionshaeuser