I had this problem with WordPress 3.4.2 and have upgraded to the latest version of wordpress. The problem remains. It is only affecting a couple of pages on my site now. Not even all the pages. It did affect all the posts as well, but now my posts are fine. I had to uninstall Jetpack to get the posts to appear normal.
This problem is across browsers and has been present in two different templates (Twenty Ten and now Artisteer). It is most definitely a jetpack problem. I have a sandbox where I tested the new theme. On that site there is no issue with content above the header.
The problem: All the content is written above the header. Scroll down below the header and you will see the same content properly formatted. I read on Yoast something about open graph tags. I would like to know if there is a simple line of code I can put into the php file of the template to fix this? What is the code and exactly where does it go?
here is example: http://healthy-family.org/about/advertise/
If you click on a few other pages they will display properly. Nothing above the header.
I like jetpack, I really do.... But this is a headache that makes it seem like too much trouble.
I have deactivated other plugins. The problem remains until I deactivate Jetpack.