Broken characters in Kashida in dev version

[hadisfr]

Hi Vafa!

Brief outline of the issue

Different difficulties have been known for using Kashida options. With recent changes, many of them seems to be fixed.

It seems that recent unreleased commit a91d9bc will make some of the fixed problem reappear.

Minimal example showing the issue

\documentclass{article}
\usepackage{bidipoem}
\usepackage[localise, Kashida]{xepersian}
\settextfont{XB Niloofar}
\begin{document}
\begin{traditionalpoem}
من آن مرغ سخندانم که در خاکم رود صورت&
هنوز آواز می‌آید به معنی از گلستانم
\end{traditionalpoem}
\end{document}

Expected behavior

(Seen in v23.1, 2020/05/17)

Actual behavior

(Seen after patching a91d9bc)

Log and PDF files

xepersian_poem_002.log
xepersian_poem_002.pdf