Eli Zaretskii <eliz@gnu.org> writes:

> Which seems to clearly indicate that this _is_ font-dependent, right?
>
> Moreover, it seems also to hint on the reason for the issue: the
> correct display uses only 2 glyphs, whereas the incorrect display uses
> 3 glyphs.  Which means -- and that matches my observations on my
> systems -- that the "good" font has a precomposed glyph for
> shadda-kasrah, while the "bad" font doesn't.  And the composition data
> in the latter case indicates that we were told to display the kasrah
> below the base character (the descent value is positive).

Makes sense.

> Can someone please see what HarfBuzz's hb-view produces from these
> glyphs, with the same fonts as you see in Emacs?  If hb-view produces
> the same display for the same fonts, then it's not an Emacs problem,
> and we should ask the HarfBuzz developers what, if anything, HarfBuzz
> can do better for the problematic fonts.  And if hb-view does better
> than Emacs, then we should ask the HarfBuzz developers to help us
> understand what we do incorrectly in this case.

Emacs and hb-view seem to be in agreement: