https://math.codidact.com/questions/278763 reports a problem where somebody tried to use \ to create a newline in mathjax, which failed. It failed because \ needs to be escaped in markdown, so you have to write \\. See also https://math.codidact.com/questions/278270.

I don't know if there are other special cases besides .

Could we find a place in the mathjax help topic to cover this?