bug#29767: 26.0.90; Failing auto-fill in message-mode because of bad state (comment-skip-end)

[Eli Zaretskii]

> From: Michael Heerdegen <michael_heerdegen@web.de>
> Date: Tue, 19 Dec 2017 12:52:30 +0100
> Cc: 29767@debbugs.gnu.org
> 
> "Jose A. Ortega Ruiz" <jao@gnu.org> writes:
> 
> >   - sometimes, when composing a reply to an email in gnus (major mode is
> >     message-mode there, auto-fill-mode is enabled), when a line is
> >     auto-filled and broken in two, do-auto-fill incorrectly thinks that
> >     it is inside a comment and adds a `> ' prefix to it.
> 
> This has bugged me for a long time.  I also don't have a recipe, the
> issue has a Heisenbug-like behavior.  But it happens quite often - it
> >     even happens right now, I didn't comment this line.

What does "C-h l" show immediately after this happens?