Gnus mail splitting rule stopped working; not sure why.

[Pankaj Jangid]

Hi,

I have this in my Gnus settings:
  
(setq nnmail-split-methods
    '(("list.numpy" "List-Id:.* <numpy-discussion.python.org>")
      ("list.mutt" "List-Id:.* <mutt-users.mutt.org>")))

Any idea why the "list.mutt" rule is not applying? Following is a
snippet from headers of an email from the mutt mailing list.

OpenPGP: id=ADEF768480316BDA; 
url=http://www.8t8.us/configs/80316BDA.asc.pubkey; preference=signencrypt
User-Agent: Mutt/1.12.2+161 (9506db1e) (2019-10-01)
X-BeenThere: mutt-dev@mutt.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: <mutt-dev.mutt.org>
List-Unsubscribe: <http://lists.mutt.org/mailman/options/mutt-dev>, 
<mailto:mutt-dev-request@mutt.org?subject=unsubscribe>
List-Archive: <http://lists.mutt.org/pipermail/mutt-dev/>
List-Post: <mailto:mutt-dev@mutt.org>
List-Help: <mailto:mutt-dev-request@mutt.org?subject=help>
List-Subscribe: <http://lists.mutt.org/mailman/listinfo/mutt-dev>, 
<mailto:mutt-dev-request@mutt.org?subject=subscribe>

(Sorry for longer verbatim lines above)

Also note that the rule was working a few days ago. It is only recently
that it has stopped working and sending emails to my inbox-group.

-- 
Regards,
Pankaj Jangid