Hamburger menu error javascript on mobile site

my site: https://www.dcidentalclinic.com/

I have a big problem. I use smilepure theme and on mobile device, hamburger menu firstly loading wide and than normal, but this situation is bad and loading page 5-7 second. below image, How can I resolve this problem? can you help me?

enter image description here

I used litespeed cahce plugin but dont resolve this problem.