If you plan to use multipages for all pages, I can help create a custom version that remove the ONE PAGE smoothscroll feature.
If you plan to use both one page scroll and multipage pages for other menu items, simply add class no-scroll for the menu items that not using anchor link (to avoid the #undefined issue).
In Menu Manager -> Menu Item -> choose “Helix Menu Options” tab from menu settings, then in Custom CSS Class, just add the custom css class no-scroll (Screenshot https://imgur.com/ZkGS8Hg )