After Activating Main Menu Disappeared

Hi there,

its an awesome plugin. Scroll works really well. but once the smooth scroll is activated the main menu will be disappeared after scrolling down beyond viewport. Sticky menu did not further function. after scrolling up menu appeared sometimes after only hover.. check the below video.

https://www.awesomescreenshot.com/video/16809644?key=4c6f10a0b1d9b2624ff9ff03cc4df7d8

please let me know how we can work this out.

Thank you for the tremendous work!