Hi,
I’m not sure I see what you mean. I’ve checked the site and noticed no issues on the links.
Your menu items are jump links. Smooth scrolling only works on same page navigation using it.
Perhaps you were expecting these links to behave in a way where it starts on top and then smooth scroll down to the section its suppose to go but I’m afraid jump links don’t work that way.
They just go directly to the section on the page they are linked when you are coming from another page.