Perhaps we might create here some examples which illustrate the bug. (So that it is not necessary to rely on a link to a post on the main site.)

Whether the bug manifests or not might depend on many various aspects, but some longish centered formulas should probably suffice to illustrate the problem. (Most likely they will be a bit artificial, but that doesn't really matter that much if the purpose is to illustrate behavior of some specific MathJax renderer.)

This answer is community wiki - do not hesitate to edit it further, if you have suitable additions.

Let us define $f$ and a set of functions $\{g_n\}$ as follows:
$$f:[0,T]\mapsto\mathbb{R}\textrm{ s.t. } f(t)>0,\forall t \in[0,T]$$
$$\{g_n:\mathbb{R}\mapsto\mathbb{R}^+\}\textrm{ a set of Lipschitz functions such that }\exists K>0,\forall n, \forall t\in[0,T] \textrm{ s.t. } 0 < g_n(t) \leq K <+\infty $$

$$\lim\limits_{n\to\infty} x_n = a \Longleftrightarrow (\forall U\in \mathcal O_a)(\exists n_0)(n\ge n_0 \Rightarrow x_n\in U)
\Longleftrightarrow (\forall \varepsilon>0)(\exists n_0)(n\ge n_0 \Rightarrow |x_n-a|<\varepsilon)$$

$$
\begin{vmatrix}
1 & 3 & 1 & 2 \\
2 & 3 & 0 & 1 \\
1 & 0 & 1 & 3 \\
0 & 2 & 1 & 1 \\
\end{vmatrix}=
\begin{vmatrix}
1 & 3 & 1 & 2 \\
1 & 0 &-1 &-1 \\
1 & 0 & 1 & 3 \\
0 & 2 & 1 & 1 \\
\end{vmatrix}=
\begin{vmatrix}
0 & 3 & 0 &-1 \\
0 & 0 &-2 &-4 \\
1 & 0 & 1 & 3 \\
0 & 2 & 1 & 1 \\
\end{vmatrix}=
\begin{vmatrix}
0 & 3 & 0 &-1 \\
0 & 0 &-2 &-4 \\
1 & 0 & 1 & 3 \\
0 & 2 & 1 & 1 \\
\end{vmatrix}=
2\begin{vmatrix}
0 & 1 &-1 &-2 \\
0 & 0 &-1 &-2 \\
1 & 0 & 1 & 3 \\
0 & 2 & 1 & 1 \\
\end{vmatrix}=
2\begin{vmatrix}
0 & 1 & 0 & 0 \\
0 & 0 &-1 &-2 \\
1 & 0 & 0 & 1 \\
0 & 2 & 0 &-1 \\
\end{vmatrix}=
2\begin{vmatrix}
0 & 1 & 0 & 0 \\
0 & 0 &-1 &-2 \\
1 & 0 & 0 & 1 \\
0 & 0 & 0 &-1 \\
\end{vmatrix}=
2\begin{vmatrix}
1 & 0 & 0 & 1 \\
0 & 1 & 0 & 0 \\
0 & 0 &-1 &-2 \\
0 & 0 & 0 &-1 \\
\end{vmatrix}=2
$$

For comparison, this is the same text if we use inline formulas rather than centered formulas.

Let us define $f$ and a set of functions $\{g_n\}$ as follows:
$f:[0,T]\mapsto\mathbb{R}\textrm{ s.t. } f(t)>0,\forall t \in[0,T]$,
$\{g_n:\mathbb{R}\mapsto\mathbb{R}^+\}\textrm{ a set of Lipschitz functions such that }\exists K>0,\forall n, \forall t\in[0,T] \textrm{ s.t. } 0 < g_n(t) \leq K <+\infty $

$\lim\limits_{n\to\infty} x_n = a \Longleftrightarrow (\forall U\in \mathcal O_a)(\exists n_0)(n\ge n_0 \Rightarrow x_n\in U)
\Longleftrightarrow (\forall \varepsilon>0)(\exists n_0)(n\ge n_0 \Rightarrow |x_n-a|<\varepsilon)$

$
\begin{vmatrix}
1 & 3 & 1 & 2 \\
2 & 3 & 0 & 1 \\
1 & 0 & 1 & 3 \\
0 & 2 & 1 & 1 \\
\end{vmatrix}=
\begin{vmatrix}
1 & 3 & 1 & 2 \\
1 & 0 &-1 &-1 \\
1 & 0 & 1 & 3 \\
0 & 2 & 1 & 1 \\
\end{vmatrix}=
\begin{vmatrix}
0 & 3 & 0 &-1 \\
0 & 0 &-2 &-4 \\
1 & 0 & 1 & 3 \\
0 & 2 & 1 & 1 \\
\end{vmatrix}=
\begin{vmatrix}
0 & 3 & 0 &-1 \\
0 & 0 &-2 &-4 \\
1 & 0 & 1 & 3 \\
0 & 2 & 1 & 1 \\
\end{vmatrix}=
2\begin{vmatrix}
0 & 1 &-1 &-2 \\
0 & 0 &-1 &-2 \\
1 & 0 & 1 & 3 \\
0 & 2 & 1 & 1 \\
\end{vmatrix}=
2\begin{vmatrix}
0 & 1 & 0 & 0 \\
0 & 0 &-1 &-2 \\
1 & 0 & 0 & 1 \\
0 & 2 & 0 &-1 \\
\end{vmatrix}=
2\begin{vmatrix}
0 & 1 & 0 & 0 \\
0 & 0 &-1 &-2 \\
1 & 0 & 0 & 1 \\
0 & 0 & 0 &-1 \\
\end{vmatrix}=
2\begin{vmatrix}
1 & 0 & 0 & 1 \\
0 & 1 & 0 & 0 \\
0 & 0 &-1 &-2 \\
0 & 0 & 0 &-1 \\
\end{vmatrix}=2
$