# System keeps rejecting latex in questions

In my last two questions, whenever I tried pasting mathjax, the system would tell me that I am trying to paste code without code-syntax, and that I should please change that. For example,

I cannot post this in this question:

$$H(s) = \begin{cases} 0 & \text{ if } s < n_0 \ e^{\lambda (s - n_1)} & \text{ if } n_0 \leq s \leq n_1 \ 1 & \text{ if } s > n_1 \end{cases}$$

I posted it with the code tags, and A golden user could then edit the tags out on my behalf. Even now that the latex is edited into the question, I cannot save changes myself anymore (even if I do no changes, because it keeps telling me that

Your post appears to contain code that is not properly formatted as code. Please indent all code by 4 spaces using the code toolbar button or the CTRL+K keyboard shortcut. For more editing help, click the [?] toolbar icon.

I wonder whether low rep users are not supposed to use mathjax on this site, or whether this is a legitimate bug?