It appears that Stack Exchange sites with MathJax support have been having some problems with tables and matrices being wider than the question and answer area of the site, leading to text mixing in with the sidebars.
- Out of question body area bound MathJax-ed matrices
It is possible that this answer to the MathJax bug reporting question may be related, but I am not an expert, so can't tell whether it is the same issue or not?
I have checked these pages on both my Linux and Windows workstations, using a mix of web browsers. The wide Robotics matrix and \tag problem can be seen on all browser/OS combinations I've tried, but I only see the table fit problem on Linux (both Firefox ESR 45.4.0 and Chromium 53), I don't see them on Windows 10 (Firefox 49, Chrome 54 or Edge 38).