Issue with modal window size using Colorbox

I am using jQuery 1.8.2 on the site, and when I attempt to use the Colorbox plugin and initiate the modal window for a gallery, the modal window fills the entire height of the page vs the entire height of the viewport.

You can see an example here:

If you click on one of the 6 images at the bottom of the first section, the modal window has some issues with size.

Anyone have any ideas what causes this?