Posts rendering different than pages since 2.9 upgrade

I have an issue that has just baffled myself and a few other WP guys that I have consulted with. After upgrading to 2.9 my posts render differently than my pages in IE.

The posts (I pull in custom templates based on categories) render fine in both IE and Firefox. All is good.

On pages a space is added at the top of the page in IE, Firefox and my Blackbrerry browser. In IE and my Blackberry browser some of the CSS is ignored, the sidebars appear in different positions from page to page (using a number of templates), sometimes the left sidebar is pushing the right sidebar down the page, images in the sidebars are being cropped (likely CSS overflow or size attributes?) and the positioning is screwed up.

The site has been running for about 9-10 months and everything worked perfect before I upgraded to 2.9. I re-installed when 2.9.2 came out and it did not fix any of the issues I was having.

I printed out the source code from the posts and a page and went through line for line. I could not see any differences.

It also doesn’t make sense that both use the same header file and left sidebar file but they render differently.

I’m stumped.

Anyone have any ideas of where I should be looking?

Thanks in advance.