# What causes raw TeX code to appear on Questions page but not on question's own page?

I was just curios about occasional occurrences such as this one where raw TeX code shows up in the description of the problem on Questions page (but not in the page for the question itself).

The preview consists of $n$ characters.
If the MathJax code begins within these $n$ characters, but does not terminate within that limit, the site won't compile it.