Exam + amsmath does not compile in some cases

[HirbodBehnam]

Brief outline of the issue

Hello
There is a problem in xepersian that prevents you to compile exam documents that are have a . in one gather or align block of their questions.
For instance, the minimal example I supplied can be compiled with either removing xepersian package, removing the . (dot) between 1 and 2 or changing the document class to article for example. It looks like that the problem is related to the ..

Check/indicate

• Relevant to the bidi package
• The bidi package issue tracker has been searched for similar issues?
• The xepersian package issue tracker has been searched for similar issues?
• Links to <tex.stackexchange.com> discussion if appropriate
• Links to <qa.parsilatex.com> discussion if appropriate

Minimal example showing the issue

% !TEX TS-program = XeLaTeX
% !TEX encoding = UTF-8 Unicode
\documentclass{exam}
\usepackage{amsmath}
\usepackage{xepersian}
\settextfont{XB Niloofar}
\begin{document}
\begin{questions}
\question
\begin{gather*}
a = 1.2
\end{gather*}
\end{questions}
\end{document}

Expected behavior

PDF compiles successfully.

Log and PDF files

This is XeTeX, Version 3.141592653-2.6-0.999995 (TeX Live 2023) (preloaded format=xelatex)
 restricted \write18 enabled.
entering extended mode
(./main.tex
LaTeX2e <2022-11-01> patch level 1
L3 programming layer <2023-02-22>
(/usr/local/texlive/2023/texmf-dist/tex/latex/exam/exam.cls
Document Class: exam 2021/02/26 Version 2.7 by Philip Hirschhorn
(/usr/local/texlive/2023/texmf-dist/tex/latex/base/ifthen.sty)
(/usr/local/texlive/2023/texmf-dist/tex/latex/base/article.cls
Document Class: article 2022/07/02 v1.4n Standard LaTeX document class
(/usr/local/texlive/2023/texmf-dist/tex/latex/base/size10.clo)))
(/usr/local/texlive/2023/texmf-dist/tex/latex/amsmath/amsmath.sty
For additional information on amsmath, use the `?' option.
(/usr/local/texlive/2023/texmf-dist/tex/latex/amsmath/amstext.sty
(/usr/local/texlive/2023/texmf-dist/tex/latex/amsmath/amsgen.sty))
(/usr/local/texlive/2023/texmf-dist/tex/latex/amsmath/amsbsy.sty)
(/usr/local/texlive/2023/texmf-dist/tex/latex/amsmath/amsopn.sty))
(/usr/local/texlive/2023/texmf-dist/tex/xelatex/xepersian/xepersian.sty
(/usr/local/texlive/2023/texmf-dist/tex/latex/fontspec/fontspec.sty
(/usr/local/texlive/2023/texmf-dist/tex/latex/l3packages/xparse/xparse.sty
(/usr/local/texlive/2023/texmf-dist/tex/latex/l3kernel/expl3.sty
(/usr/local/texlive/2023/texmf-dist/tex/latex/l3backend/l3backend-xetex.def)))
(/usr/local/texlive/2023/texmf-dist/tex/latex/fontspec/fontspec-xetex.sty
(/usr/local/texlive/2023/texmf-dist/tex/latex/base/fontenc.sty)
(/usr/local/texlive/2023/texmf-dist/tex/latex/fontspec/fontspec.cfg)))
(/usr/local/texlive/2023/texmf-dist/tex/xelatex/xepersian/xepersian-persiancal.
sty)
(/usr/local/texlive/2023/texmf-dist/tex/xelatex/xepersian/xepersian-mathdigitsp
ec.sty) (/usr/local/texlive/2023/texmf-dist/tex/xelatex/bidi/bidi.sty
****************************************************
* 
* bidi package (Bidirectional typesetting in
* plain TeX and LaTeX, using XeTeX engine)
* 
* Description: A convenient interface for
* typesetting bidirectional texts in plain TeX
* and LaTeX. The package includes adaptations
* for use with many other commonly-used packages.
* 
* Copyright (c) 2007--2023 Vafa Khalighi
* Copyright (c) 2018--2020 bidi-tex GitHub organization
* 
* v39.7 (Release Serge Lang), 2023/01/18
* 
* License: LaTeX Project Public License, version
* 1.3c or higher (your choice)
* 
* Location on CTAN: /macros/xetex/latex/bidi
* 
* Issue tracker: https://github.com/kvafa/bidi/issues
* 
* Discussions: https://github.com/kvafa/bidi/discussions
* 
* Primary author of bidi package: Vafa Khalighi.
* 
****************************************************
(/usr/local/texlive/2023/texmf-dist/tex/generic/iftex/iftex.sty)
(/usr/local/texlive/2023/texmf-dist/tex/xelatex/bidi/biditools.sty)
(/usr/local/texlive/2023/texmf-dist/tex/latex/zref/zref-abspage.sty
(/usr/local/texlive/2023/texmf-dist/tex/latex/zref/zref-base.sty
(/usr/local/texlive/2023/texmf-dist/tex/generic/ltxcmds/ltxcmds.sty)
(/usr/local/texlive/2023/texmf-dist/tex/generic/infwarerr/infwarerr.sty)
(/usr/local/texlive/2023/texmf-dist/tex/latex/kvsetkeys/kvsetkeys.sty)
(/usr/local/texlive/2023/texmf-dist/tex/generic/kvdefinekeys/kvdefinekeys.sty)
(/usr/local/texlive/2023/texmf-dist/tex/generic/pdftexcmds/pdftexcmds.sty)
(/usr/local/texlive/2023/texmf-dist/tex/generic/etexcmds/etexcmds.sty)
(/usr/local/texlive/2023/texmf-dist/tex/latex/auxhook/auxhook.sty))
(/usr/local/texlive/2023/texmf-dist/tex/latex/base/atbegshi-ltx.sty))
(/usr/local/texlive/2023/texmf-dist/tex/latex/xkeyval/xkeyval.sty
(/usr/local/texlive/2023/texmf-dist/tex/generic/xkeyval/xkeyval.tex
(/usr/local/texlive/2023/texmf-dist/tex/generic/xkeyval/xkvutils.tex
(/usr/local/texlive/2023/texmf-dist/tex/generic/xkeyval/keyval.tex))))
(/usr/local/texlive/2023/texmf-dist/tex/xelatex/bidi/latex-xetex-bidi.def
(/usr/local/texlive/2023/texmf-dist/tex/xelatex/bidi/footnote-xetex-bidi.def)
(/usr/local/texlive/2023/texmf-dist/tex/xelatex/bidi/article-xetex-bidi.def)
(/usr/local/texlive/2023/texmf-dist/tex/xelatex/bidi/amsmath-xetex-bidi.def)
(/usr/local/texlive/2023/texmf-dist/tex/xelatex/bidi/amstext-xetex-bidi.def))
(/usr/local/texlive/2023/texmf-dist/tex/xelatex/bidi/loadingorder-xetex-bidi.de
f))
****************************************************
* 
* xepersian package (Persian for LaTeX, using XeTeX engine)
* 
* Description: The package supports Persian
* typesetting, using fonts provided in the
* distribution.
* 
* Copyright (c) 2008--2022 Vafa Khalighi
* Copyright (c) 2018--2020 bidi-tex GitHub Organization
* 
* v24.8 (Release Women, Life, and Freedom), 2022/10/30
* 
* License: LaTeX Project Public License, version
* 1.3c or higher (your choice)
* 
* Location on CTAN: /macros/xetex/latex/xepersian
* 
* Issue tracker: https://github.com/kvafa/xepersian/issues
* 
* Discussions: https://github.com/kvafa/xepersian/discussions
* 
* Primary author of xepersian package: Vafa Khalighi.
* 
****************************************************

(/usr/local/texlive/2023/texmf-dist/tex/xelatex/xepersian/loadingorder-xepersia
n.def)
(/usr/local/texlive/2023/texmf-dist/tex/xelatex/xepersian/footnote-xepersian.de
f)
(/usr/local/texlive/2023/texmf-dist/tex/xelatex/xepersian/article-xepersian.def
)) (./main.aux) (/usr/local/texlive/2023/texmf-dist/tex/latex/base/ts1cmr.fd))
! Incomplete \ifx; all text was ignored after line 10.
<inserted text> 
                \fi 
<*> main.tex
            
?