bug#34035: 26.1; Arabic shadda-kasrah renders incorrectly

[Peter]

- Start emacs -Q
- C-\ arabic RET
- s ~ A (sin shadda kasrah) repeat a few times

The kasrah (short slash below the letter) should be shown below the
shadda (the squiggle above the letter) and above the letter, not below
it.

I've tried different fonts, this seems to be a problem with emacs
itself, other editors and firefox render the same text (copy-pasted)
correctly.

See attached screenshot for what it looks like in Emacs and in Firefox.

Thanks for any help with this!

Greetings, Peter

emacs-shadda-kasrah.png
Description: PNG image

firefox-shadda-kasrah.png
Description: PNG image