The problem is in every PC me and my friend tested, mostly on Chrome, but does not matter, I solved.
The pages in this layout seem to have a "default" height (in fact, I read that someone had problems trying to make them shorter and avoid too much white space).
I simply had a page with a very long content which sometime overlapped the footer.
I solved putting a div with a minimum height outside the content of the page:
<div style="min-height: 1500px;">
...
...
veeeeeery long page html content
...
...
</div>
Not the best practice maybe, but works.