Weird bug with menu

Hello everybody! I noticed a weird bug with the nav bar, it is happening only on one page of the website. As you can see from the gif, when the menu is in his original position it’s simply not working, but as soon as I scroll down a little all the links become active and work properly.
Anyone has an idea why is this happening??
The menu is the same on every page but only one has this problem!:crazy_face: