Hi Nelo, you have double animation. We had that problem to. Just make the preloader ON and it will be solved. And my question is why do you have two menus. One on bottom and second one on the top right side (hamburger menu)?
I think it was for pleasure, it made me interesting a visible menu, while for anything to have another at the top !! in particular I do not like the preloader, but if necessary I will apply it.