When I view the published documentation in IE10 & Firefox 16.0.1
Font family in CSS is Arial.
This does not happen when viewing the same documentation in IE using Compability View (to view as if IE9). In fact, this issue only occurred in IE since moving to IE10. Not sure about previous versions of Firefox.
I have applied the patch provided by William to RH9 for viewing on IE10.
I have also verified that font options are unchecked in IE's Internet Options > Accessibility window.
At the moment, I can't confirm this occurs when viewing on another machine.
RH 188.8.131.521, Webhelp
Very weird. Do these extra bold texts by change have both the inline styling as well as a css attached? I think I’ve seen a similar issue that revolved around bold text within bold text.
Another solution may be to find and replace you bold styles with CSS classes.