# Previewed post does not match rendered post when MathJax uses *

In revision 2 of Number of permutations in $$S_{a + b}$$ with $$\operatorname{maj}(\pi) = b$$ and $$\operatorname{maj}(\pi^{-1}) = b$$, I edited an equation that had been manually given the label (\ast) to use \tag. As usual when I have to make up a label for an equation that wasn't already given one, I used the existing tag; in this case, \label{*}, with the corresponding \eqref{*}. This worked fine in the generated preview, but, when the post actually rendered, the * inside \eqref was parsed as Markdown rather than as MathJax.

@GeraldEdgar's test suggests that this might not happen on MMO (or maybe we're not exercising the specific buggy conditions here?), but visiting the specific revision https://mathoverflow.net/revisions/384561/2 shows that it does happen on MO.

In case TeX in the main post affects @GeraldEdgar's test, $$1 + 2 = 3$$. In case you missed it, $$$$\tag{*}\label{*} 1 + 2 = 3.$$$$ In case you still missed it, refer back to \eqref{*}

• An obvious answer is "don't use * as a label", which will certainly mitigate the problem, but my point is more about the preview not matching the rendered post than working around this specific parsing issue. – LSpice Feb 21 at 18:28
• Your equation in the question looks OK when I first come here, but goes bad when I edit. – Gerald Edgar Feb 27 at 11:46

Trying to reproduce the problem. An equation $$4+2=9 \tag{*}\label{1}$$ and then reference to it \eqref{1}. How does it look?
Another equation $$4\times2 = 6 \tag{**}\label{2}$$ and a reference to it \eqref{2}. How does it look?