bug#41626: 28.0.50; activating mark breaks RTL shaping in etc/HELLO (auto-composition-mode)

[Pip Cet]

On Sun, May 31, 2020 at 12:40 PM Basil L. Contovounesios
<contovob@tcd.ie> wrote:
> > The same thing works fine in a separate buffer in an RTL paragraph.
> FWIW, a similar thing was discussed in bug#35721.

Thanks for the hint!

What I don't understand is why it works in pure RTL paragraphs,
though. If I yank the Arabic greeting into a new buffer, I can place
the mark anywhere and nothing happens to the shaping.