When I visit http://stackoverflow.com/questions, I see exactly one question per page (tested over several pages), with normal paging controls. This only happens when I'm logged in.
I checked my account settings; the only thing that seems possibly relevant is my long list of ignored tags, but I do not have “hide ignored tags” turned on, and this is still arguably buglike even if that is the cause.
On the other hand, the next page loads quite snappily! :)