I think this may be a known issue - but not sure if fix available as yet.
It seems the footer on the home page behaves as if there is a module in the 'footer2' position, whereas it's normal on all other pages.
For example check my site on a large screen.. the home page has the footer text occupying just the left half of the footer area, and if you load http://mysite.com/?tp=1
you can see the footer2 position is being loaded. Then go to any other page on my site and the footer displays as intended (full width because there are no modules in 'footer2' position.