Hybrid Main Navigation Links

I have an issue with our main navigation links. As demonstrated on the site below:

https://www.corporatevoice.com

The first 3 links in the main nav are anchor links on the same page (home). The 4th link is to a contact page. The links all work great however once you click on the contact page and from there try to navigate to one of the first 3 links again it breaks. The URLs are formatting themselves as if the anchors are on the contact page from there. How can I link the nav items so they work regardless of what page you’re on?

Thanks in advance.