I'm trying to fix this bug in IE8 for this page
http://www.mintankesmie.no/innovasjon.php

It seem like it is a render problem but I can not find the real reason of this bug

The problem is text is not display in some part of the middle section.
However, it will display after you move a mouse over it or select it.

I found the similar bug in sitepoint and they suggest to add
visibility:visible;

Unfortunately it doesn't help me fix this bug.

Is there anyone have this kind of problem before and how to fix it?