WP Post Grid Effecting Navigation Menu: Causing menu to hover to the left

Hello,

Adding Post Grid element to any page on the website causes the navigation menu to hover to the left, creating a large empty left margin next to the nav bar. Only by removing Post Grid, the problem ceases. What could be wrong? I am sure its not in the website because other elements work fine. Any advice would be appreciated.

Thank you.

The page I need help with: [log in to see the link]