I'm using the latest firefox 26.0 in PClinux and the MathJax doesn't render which makes it very difficult to read the edits. Using Google Chrome v31 I get the same result.
But both work fine when I read posted messages or in edit mode
Update: I have checked the edits I have approved that included MathJax and it seems that some do get rendered and some don't.
These get rendered:
But these do not:
So there seems to be something that triggers this behaviour.