When you setup the megamenu to have multiple of the same links in the menu, for example:

Main Navigation:
Home
Wines
– All Wines (Goes to same link as Wines above)
– Red Wines
– …

When you set 2 items to have the same CMS Type & Page, it causes a PHP error when you visit that page.

To recreate:
1. Create a main menu entry to an existing CMS page (not external link).
2. Create a sub menu entry to the same existing CMS page (using CMS type again).
3. Visit the site and click the main menu entry link, and the sub menu entry link. You should be presented with a PHP parse error.