During the discussion of Dollar Sign corrupts question we determined that $ needed to be escaped on sites that have LATEX enabled.
However, when escaping multiple $, we found that initial \$ was fine, but that the second one maintained the "\".
The specific site was http://robotics.stackexchange.com/questions
As of this writing, the post in question is the second from the top. Contributors to my initial meta-site question and I believe this to be a bug.