If I add <math>A' = \pi</math> to the sandbox, and save (or just preview, as in the link above), and MathJax is enabled in my preferences, I see the following errors on console (Google Chrome 32.0.1700.107):

GET https://bits.wikimedia.org/static-1.23wmf13/extensions/Math/modules/MathJax/fonts/HTML-CSS/TeX/woff/MathJax_Greek-BoldItalic.woff 404 (Not Found)

GET https://bits.wikimedia.org/static-1.23wmf13/extensions/Math/modules/MathJax/fonts/HTML-CSS/TeX/woff/MathJax_Greek-Bold.woff 404 (Not Found)

GET https://bits.wikimedia.org/static-1.23wmf13/extensions/Math/modules/MathJax/fonts/HTML-CSS/TeX/woff/MathJax_WinIE6-Regular.woff 404 (Not Found)

I first noticed this error at
https://en.wikipedia.org/wiki/Wikipedia:Village_pump_(technical)?oldid=595462948

Version: unspecified
Severity: normal
URL: https://en.wikipedia.org/wiki/WP:Sandbox?oldid=595470989&action=edit&preview=yes