added to tl (some time ago), think there is nothing more to do here, closing ...

Reference

https://tex.stackexchange.com/questions/547131/texh4t-produces-bad-table-of-content-when-some-math-is-used-with-mathjax-mode

I noticed when I have some math in section names, sometimes the table of content is corrupted, even though the same math displayed OK in the body of the section.

Here is a MWE
==========================
\documentclass[12pt]{article}
\usepackage{amsmath}
\begin{document}
\tableofcontents
\section{bad section $\sum\limits_{i=1}^n \frac{1}{(x (n-i)+i)^2}$}
This is my section

$\sum\limits_{i=1}^n \frac{1}{(x (n-i)+i)^2}$

\section{good section $\sin(x)$}
This is my section

$\sin(x)$
\end{document}
======================

Compiled using

make4ht -ulm default foo3.tex "htm,mathjax"

gives screen shot shown in link above.

When compiled not using mathjax mode, the table of content is correct.

The \DOTSB seems to be generated by tex4ht and not mathjax, since the raw HTML shows this

=====================
<span class="sectionToc" >1 <a
href="#x1-20001" id="QQ2-1-2">bad section \(\DOTSB \sum@ \slimits@ \limits _{i=1}^n \frac{1}{(x (n-i)+i)^2}\)</a></span>
<br />
=======================

Why does tex4ht generate this extra \(\DOTSB and how to remove it?

Using TL 2020.

(base) >make4ht --version
make4ht version v0.3e