https://bugs.winehq.org/show_bug.cgi?id=57076
--- Comment #4 from Esme Povirk madewokherd@gmail.com --- Did some testing with Wingdings. The algorithm gdiplus uses produces the same result on Wine and Windows: using Arial for the full string. I also tested with Tahoma and didn't get a replacement font.
So mlang is working correctly.
I think maybe gdiplus should be checking whether glyphs exist in the base font, rather than their codepage, when deciding whether to replace them. Not sure how to test that though.