I would guess that this is a font problem.
A first step toward analyzing the problem is finding out exactly which font is used for
the distorted text and how it differs from non-distorted ones. It would also be interesting to know if the problem arrives in Firefox.
Some tools you can use are :
Firefox : The add-on Font Finder that can analyze the font, and Firebug
that can in addition list all the CSS styles that are affecting the text.
Chrome : DevTools or the extension WhatFont or Firebug Lite.
IE : Developer tools (F12) or Firebug Lite.
Please post your results of the analysis of the problematic fonts, even if not conclusive.