Sidebar Link and Comment Problem

Hey everyone. My site is https://www.xboxct.com and there is a problem on it. For some reason, when you click a link on the sidebar such as “About XCT”, then press one of the tabs at the top such as “Enter Tournament”, it goes to this:

https://www.xboxct.com/about-xct/enter-tournament
when it should just be: https://www.xboxct.com/enter-tournament.

But for some reason, this problem doesn’t happen when you click “Tournament: DOA 4”.

The same problem happens when you go to a comment page also.

I made sure nothing has a parent so why is this happening? Thanks.