Hello Daniel,
I experienced a new behaviour when browsed as a visitor on a page which shows the right color and left sidebar and 4 colums setup. The page starts OK. But when scrolling down on a category page. The setup seems to change to 3 or 2 colums and the colum size and changes the width.
I have some screenshots, but I do not know how to insert here.
When I log in as a an administrator, everything shows fine.