Single Page Scroll behaving inconsistently

Hello,

I have a site which I am building in the form of a single page scroll, with menu items linked to colour sections using Section ID’s.

All menu items are working correctly (i.e the page scrolls down to the correct section when clicked). However the second menu item appears to be reloading the page and just appearing at the desired section when clicked – not smooth scrolling like the others.

Is there a way to fix this?

Thanks in advance