Bad interraction between bidi option and mathtools package in align environment

[yrogge]

Using the new 3.70 version with luaLaTeX, there is a strange behavior in align environment. See example below. With both bidi=basic option (line 4) and \usepackage{mathtools} (line 7), there are errors in align (at line 23). Commenting either one, the tags in it are misplaced.

\documentclass[a4paper,twoside,10pt,english]{article}
\usepackage[no-math,silent]{fontspec}
\usepackage[
  bidi=basic, % not compatible with package mathtools
]{babel}
\usepackage{amsmath}
\usepackage{mathtools} % not compatible with bidi option
\renewcommand{\familydefault}{\sfdefault} % Pour polices sans empattement
\babelfont{rm}{Noto Serif}     % alias \setmainfont
\babelfont{sf}{Noto Sans}      % alias \setsansfont
\babelfont{tt}{Noto Sans Mono} % alias \setmonofont (no Italic, no Bold Italic)
\usepackage{lualatex-math}
\usepackage{unicode-math}      % => \setmathfont
\setmathfont[StylisticSet={8,11,16}]{STIX Two Math} % upint, neg.set, circled op. (+ \mathscr)
\usepackage[basic,asterisk,unicodeminus,defaultmathsizes]{mathastext}
\begin{document}
\section{Test}
Lorem ipsum dolor sit amet, consectetuer adipiscing elit.
\begin{align}
  W(X,Y)
    &= \frac{1}{q^\varrho}\ \left( \Bigl( Y+(q\!-\!1)X \Bigr)^\frac{q^\varrho-1}{q-1} + (q^\varrho-1)\ \Bigl( Y-X \Bigr)^{q^{\varrho-1}}\,\Bigl( Y+(q\!-\!1)X \Bigr)^\frac{q^{\varrho-1}-1}{q-1} \right) \\
    &= \Bigl( Y+(q\!-\!1)X \Bigr)^\frac{q^{\varrho-1}-1}{q-1} \left[ \frac{1}{q^\varrho}\ \Bigl( Y+(q\!-\!1)X \Bigr)^{q^{\varrho-1}} + \left( 1 - \frac{1}{q^\varrho}\ \right) \Bigl( Y-X \Bigr)^{q^{\varrho-1}} \right]
\end{align}
\end{document} 

[yrogge]

NB. Everything was OK with version 3.67.

[jbezos]

As a workaround, try with:

\usepackage{amsmath}
\usepackage{mathtools} % not compatible with bidi option
\makeatletter
\let\save@intertext\intertext@
\AtBeginDocument{\let\intertext@\save@intertext}
\makeatother

Babel patches for \intertext are meant for amsmath, but mathtools changes this command further and the definition is messed up.

[yrogge]

OK. It works. Thank you. But there is now another strange behavior: after tagged environments (equation, align, etc.), the following non-math text is always indented as at the begin of a new paragraph. It is not the case if there were no tags ([ ], align*, etc.). Note that it is not the case when the text is produced inside the environment with \intertext or \shortintertext macros.