Verification Keeps Popping Up

Hi,

We have a website for a client we put this plugin on. IT works fine to let you into the site, but if you click around and hit the back button on the browser and click other pages, the verification form tends to pop back up and ask for verification again. Anyway to get this to stop happening?

The website is http://www.cappellisbeerandpop.com

Thanks!

http://wordpress.org/plugins/age-verify/