Resizing a responsive site down and up again in Chrome doesn't reset some elements

I've been working on the site http://ift.tt/1j97ojV using Wordpress.

The site is responsive and works a treat generally, but in Chrome there's an annoying problem. When you shrink the browser down and then back up, the sidebar and right-side header content doesn't reset position - until hitting refresh.

I've found that if I select the div .site-main .sidebar-container styling in inspector and untick position:absolute and re-tick it, this also restores it. I haven't found a way to do the same with the header text on the right.

I'm relatively new to web dev so I may be doing something daft, but your help is appreciated.