Main navigation menu is breaking on mobile

I'm getting the exact same thing on my site.

Hi @nitin shrivastava,
Could you please elaborate on what exactly this issue is about? The hamburger toggle seems to be working fine on my end.
I'm attaching a screen recording for your reference.

You need to add a second level to your menu. It is adding a new hamburger everywhere there is a ul in a menu. So, all the second-level menus get a new hamburger.