[SOLVED..but why?] rxvt-unicode font rendering issue

[nacitar]

I have a problem where rxvt-unicode using the monospace font is rendering improperly after a a system update. At first I thought it was all in my head then I dug up an old screenshot...

Old rendering on top, new rendering on bottom. I've changed no config files at all.

http://imagebin.org/219585

Any ideas what could have caused this?

[nacitar]

Just realized that emerging rxvt-unicode with +alt-font-width it fixed the issue, but I'm still curious _why_ this was suddenly required if anyone can provide information on that.