GVim theme italics cuts off character

As kemp suggested, the issue was with the font. Switching the font to something other than fixedsys resolved the issue.

As Kemp suggested and Marco acknowledged, it's a font issue. Here's how to fix it:

:set guifont=Consolas

Or, in vimrc:

if has("gui_macvim")
  set guifont=Menlo
elseif has("gui_running")
  set guifont=Consolas
endif