@ju52 Did you read the first of this thread?
OK, I will describe the problem here again. The problem of this thread is a conflict between the Markdown spec and the MathJax spec.
When we write the next TeX document in a Markdown file.
$$
\begin{vmatrix}a & b\\
c & d
\end{vmatrix}
$$
Hugo processes the input with the goldmark (CommonMark) and we will get the following HTML output.
<p>$$
\begin{vmatrix}a & b \<br>
c & d
\end{vmatrix}
$$</p>
Since MathJax cannot process the <br>
tag, the math rendering is broken.