The kern table in the Sans ExtraLight font has the version value set to 1, which makes it a Mac OS-only table and may lead to problems at least on Windows (and perhaps on Linux). See the following two pages: http://www.microsoft.com/OpenType/OTSpec/kern.htm http://developer.apple.com/textfonts/TTRefMan/RM06/Chap6kern.html From the Microsoft page: "Apple has extended the definition of the 'kern' table to provide additional functionality. The Apple extensions are not supported on Windows. Fonts intended for cross-platform use or for the Windows platform in general should conform to the 'kern' table format specified here." From the Apple page: "Fonts targeted for the Mac OS only should use the new format; fonts targeted for both the Mac OS and Windows should use the old format." I don't know if this is an intended feature or not.
This has been fixed when all kerning tables were translated to that format, i.e. kern classes, and they are generated with the old format in the TTF files.
Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.