Thank you for answering. If you believe this is an Org problem rather than
Emacs, I shall report it as an Org bug.

Best regards
/Johan Ekenberg

Den ons 8 jan. 2025 kl 13:38 skrev Eli Zaretskii <eliz@gnu.org>:

> > From: Johan Ekenberg <johan.ekenberg@gmail.com>
> > Date: Tue, 7 Jan 2025 21:08:09 +0100
> >
> > - Start emacs: 'emacs -Q'
> > - Paste this function into the scratch buffer and evaluate it:
> >   (defun test-org-insertion-fontification ()
> >     (interactive)
> >     (let* ((chunks
> >             '("#+begin_src elisp\n"
> >               "(+ 1 2)"
> >               "\n#+end_src\n")))
> >       (insert "* NOTE: You need to run this with org-mode enabled and
> point at end of buffer\n\n")
> >       (insert "** This code block is fontified correctly\n")
> >       (insert (car chunks))
> >       (dolist (chunk (cdr chunks))
> >         (insert chunk))
> >
> >       (insert "\n** But not this code block\n")
> >       (insert (car chunks))
> >       (dolist (chunk (cdr chunks))
> >         (sit-for (/ 10 1000.0)) ; simulate chunks received over network
> and streamed into buffer
> >         ;; The following were also tested one by one instead of the
> sit-for line above:
> >         ;; (redisplay) ; this triggers the bug
> >         ;; (force-mode-line-update) ; this does not trigger the bug
> >         ;; (read-event nil nil 0) ; this triggers the bug
> >         (insert chunk))
> >       ))
> > - Open an existing or new file/buffer with org-mode enabled (C-x C-f
> foo.org)
> > - Place point at end of buffer
> > - M-x test-org-insertion-fontification
> > - Optional: replace the line (sit-for...) with any of the lines below it.
> >
> > - Additional information: The problem was discovered when receiving
> > streamed data responses via the package gptel which is an Emacs LLM
> > Client. Here is the reported issue:
> > https://github.com/karthink/gptel/issues/550
> >
> > - Also replicated on Emacs 29.3
>
> Isn't this an Org problem?  If so, could you please report this to the
> Org bug mailing list?
>