Mega Menu Cut Off

I am attempting to develop a new menu using Max Mega Menu and have almost got things configured the way I’d like, but the mega menu portion (under ‘Topics’ in the in-page nav on this example) is cutting off the bottom of the text as well as the background image I’ve styled. Any help as to how to fix would be welcome. Thanks!

http://www.fattyacidforum.com/?page_id=618&preview=true#

https://wordpress.org/plugins/megamenu/