Weird problem with footer since update 1.0.6 to 1.0.8

I’ve just updated to the latest version, and my footer is acting weird.

If I login this is my structure of the page:
* wrapper
** header
** container
** footer

The moment a normal (not logged in) user arrives, it changes to this (the footer moves from the wrapper to the container div):
* wrapper
** header
** container
*** content
*** sidebar
*** footer

This causes a wide border around my footer, since the container has a margin of 18px

Has anybody got a clue as to how I can solve this, or what might be causing it?