Hello,
In Firefox (58.0.2), the slide down animations of the menu items in Waypoint are bugged, though they behave properly in Chrome, Edge, and IE 11. Toward the end of the animation, the top of the box clips and disappears, then once the animation is finished, everything goes back to normal. Here’s a screen cap comparing the behavior in Firefox vs Chrome: https://1drv.ms/u/s!Ar-6Uspczn-fifMF2ajEunh2WfxcDw