Woocommerce Storefront Menu Issue

I am currently using Storefront theme. My main menu has two heads which have drop down menus. They work fine on desktop view. But in case of tablet view or mobile view, the main menu shows all the menu items including drop down menu, as main menu heads.

Say, my menu is Home|Products|Contact Us.

The Products Head has A|B|C sub items.

The tablet and the mobile site shows the menu as Home|Products|A|B|C|Contact Us.

Honestly, I can’t make sense of what’s going on. I have made multiple sites and blogs, but this is the first time I ma facing this issue.

An just noticed another issue. The main heads of the Drop Down Menu (here Products) when clicked, freeze the sub menu and doesn’t seems to unfreeze it unless the page is refreshed.