Sidebar beings where blog posts end

I’m sure this has been covered before, but I can’t seem to find the answer; after making a change to my blog (data-wise, not code-wise) most of my themes with sidebars now show the sidebar beginning at the bottom of my posts.

I’ve tried reformatting template after template with no different result. I know I ran into this somewhere else, but I can’t remember what I did to fix it. Could it be my links?

Anyone else have any ideas?