Loading content via AJAX destroy the font in IE.

Question

1. Look at this page.

2. Press the orange -> button and then the <- again.

This paginator shows the page 1 by default and load the other pages' content via AJAX. However, that default page 1 content and the ajax loaded page 1 content don't look the same in IE, even when the html and css are exactly the same!. You can see the font is thin and ugly, especially in the blue headers.

Why is this happening and how do I make it stop?