Now that we have MathJax, people are editing old posts to replace compromises with clear mathematical notation. I just approved an edit to this answer. In the Review Suggested Edits queue, selecting "rendered output" did not display correctly rendered MathJax. After I approved the edit, I looked up the answer and found that the MathJax was rendered correctly.
This means answers will display correctly if approved, but the decision to approve has to be made based on MathJax markup, instead of based on rendered MathJax. This makes it much more likely that a mistake will be overlooked.
Some of the MathJax was rendered in the Suggested Edits queue. My first guess is that MathJax surrounded on both sides by whitespace renders correctly, while any MathJax preceded or followed by punctuation fails to render. Putting MathJax inside a quote block also appears to prevent rendering. Both these problems are limited to the Suggested Edits queue, and display correctly once the edit is approved.
Please post an answer if you have experience of this either happening or not happening.
For me, the problem is apparent using Firefox 32.0.3 and Firefox 33.0 on Windows 7. I also checked Internet Explorer 10, and this gives a similar problem except that with Internet Explorer even MathJax surrounded on both sides by whitespace does not render in the Suggested Edits queue. Rendering is still correct after the edit is approved.