I've had this problem with a few wikipedia articles, most recently: http://en.wikipedia.org/wiki/*-algebra. The line given by * {{math|size=120%|1=(''x y'')* = ''y''* ''x''*}} doesn't display properly, the spaces in ''x y'' and ''y''* ''x'' are replaced by squares with the letters THSP in them. This problem occurs throughout the page. The same problem occurs regradless of the font I choose, but two fonts called "Clean" and "Fixed" do better than the others; they display all spaces properly apart from the space in ''λ x'' in the line given by :{{math|size=120%|1=(''λ x'' + ''μ'' ''y'')* = ''λ′'' ''x''* + ''μ′'' ''y''*}}. I don't have the same problem in Chromium, which is using the same fonts.