http://bugs.winehq.org/show_bug.cgi?id=18349
--- Comment #10 from Dmitry Timoshkov dmitry@codeweavers.com 2009-05-06 08:33:50 --- Maybe I'm reading some other bug then?
Indeed, running Notepad in Japanese locale and using System font results in this error (uppercase letters thin, lowercase thick) but using Kochi Gothic results in all letters being thin (and somewhat smaller).