`aligned` not rendering the first square bracket.

[yuxi-liu-wired]

Issue Summary

aligned not rendering the first square bracket.

Steps to Reproduce:

Try rendering this:

$$
\begin{aligned}
    [1] &= 1
\end{aligned}
$$

results in = 1

It can be bypassed by putting a curly bracket at the start.

$$
\begin{aligned}{}
    [1] &= 1
\end{aligned}
$$

This is different from the default behavior of LaTeX as rendered by pdfTeX, which renders the first square bracket without issue.

Technical details:

• MathJax Version: 3.2.2
• Client OS: Windows 11
• Browser: Chrome Version 128.0.6613.86 (Official Build) (64-bit)

I am loading MathJax via

<script src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-chtml-full.js"></script>

[dpvc]

This is a duplicate of #2888 and #3216. It is fixed in v4 (currently out in beta release). The behavior in LaTeX changed in the fall of 2020 (after MathJax v3's implementation of aligned), and that new behavior is now reflected in v4.