In FF, when looking at the page lists of articles with top images, clicking on previous to go backward through the pages does not work.  Instead of paging back, it simply changes the large ads at the right of the page. 

Clicking the page numbers works normally. 

I note this only happens when looking at articles with top image list.  When looking at the regular article pages lists, clicking on previous works as it should.

Also, it is only the previous button, the next button works normally in all cases.

I also checked MEF, and even in the old style forum the previous button doesn't work when viewing articles with top image pages.