Wordpad - Invisible text after I type "fi"

r64865, VBox 4.3.12.

Start Wordpad, don't change any settings.
Type a few letters, then type digram "fi", then a few more letters. When "fi" is written, following line will start appearing in log for each character typed

(win32ss/gdi/ntgdi/freetype.c:3606) Failed to load and render glyph! [index: 4898]

and the digram and any text following it will be invisible. Changing any font settings fixes/prevents the issue. No other lines in log.