Thanks for looking into this.
You can take a look at https://www.passievoorlezen.nl/ and I was able to reproduce it on another site as well.
I just installed Woocommerce, selected the Storefront theme and installed the Storefront Mega Menus plugin. Beside this only the Wordfence Security plugin is active. I created a menu with a menu item Shop (Winkel) and in the Mega Menu I selected the widget Product (a list of all products). Then the submenu is visible on my site. Now I install the Socials Ignited plugin and activate it, now the submenu is gone.
