Whether the font is monospace or not isn't really the problem - that causes some aesthetically ugly spacing, but that's to be expected and it's still readable.

Whether the font is monospace or not isn't really the problem - that causes some aesthetically ugly spacing, but that's to be expected and it's still readable. The big issue is that the code has completely failed to find a glyph for one of the characters used in something as commonplace as a directory listing from the dir command and people expect better than this from font rendering in modern applications.