Mobile menu not collapsing

Good morning

My primary navigation menu contains 4 items that are on 1 page and are accessed using the Page Scroll to id (Home, Services, About, Our Process). I have an additional menu item, Contacts which opens a new page.

When viewing the website on mobile device (Huawei P8 lite), if I am on the home page and click a menu item such as Services, the menu does not collapse, it stays expanded.

Help would be greatly appreciated.

The page I need help with: [log in to see the link]