This answer revision has an expression which displayed correctly in a prior Mathjax version, and also displays correctly in the edit window, but displays as [Math Processing Error] in the answer.
Revision Source
**Hint** $\rm\ 2^{\large\color{#c00}2} 3^{\large\color{#0a0}3} \mid 2^{\large\color{#c00}{2I}} 3^{\large\color{#0a0}{2J}} 5^{\large2K}\!\cdots \overset{}\Rightarrow \color{#c00}{I\ge 1},\ \color{#0a0}{J\ge 2}\ \ $ by *existence* and *uniqueness* of prime factorizations.
Output
Hint $\rm\ 2^{\large\color{#c00}2} 3^{\large\color{#0a0}3} \mid 2^{\large\color{#c00}{2I}} 3^{\large\color{#0a0}{2J}} 5^{\large2K}\!\cdots \overset{}\Rightarrow \color{#c00}{I\ge 1},\ \color{#0a0}{J\ge 2}\ \ $ by existence and uniqueness of prime factorizations.
Ditto for this answer revision.
Update I should clarify some points. The bug(s) appear to be triggered by vestigial empty \overset
expressions (probably left behind when I was pulled away from the computer in the middle of trying out different presentations). Since these expressions worked fine in the past, this may or may not indicate a bug in changes made in recent versions.
However, the fact that this error is raised only in the answer, and not in the preview, is surely another bug, since the preview rendering should correspond 100% to the answer.
\overset{}\Rightarrow
construct. Try turning off the fast preview in the MathJax contextual menu (Math Settings -> Math Renderer -> fast preview), and see if that improves the situation for you. $\endgroup$