site goes in quirk mode when viewing pages only

Hi
this is a very weird problem i can’t find the reason why:

this is a page:
https://www.vitto.mt.it/wp/contacts

this is a single post
https://www.vitto.mt.it/wp/portfolio

the code is the same but the ‘page’ must have some kind of problem which makes the browser go in quirk mode, if you the see the source code in firefox 10 you’ll see some code highlighted in red!

Does anyone has any clue?

Thanks
Vitto