Doesn't receive click on iOS (landscape orientation)

[mingyeungs]

Viewing http://wicky.nillia.ms/headroom.js/ with iPhone 6s plus (iOS 10.2) in landscape orientation.

When user swipe down (i.e. scroll up), the header div (along with the mobile safari address bar) shows up; However the links inside are not responsing to clicks (touches).

The script does work correctly (both visually and clickable) when viewing the site in portrait orientation and on desktop browsers.

[gt06]

I have also the same issue on iPhone devices in landscape and Portrait mode. When I click on hamburger menu and scroll inside sliding panel menu, header div goes along with safari browser.
Can anyone give me the solution on this?