no menu at 768px
no menu at 768px

With a window width of 768px ($screen_m) we have no menu. Mobile menu is shown below 768px and desktop above 768px, at 768px both are hidden.
gil--/magento2-theme-blank-sass,gil--/magento2-theme-blank-sass,Rocketweb-FED/magento2-theme-blank-sass,SnowdogApps/magento2-theme-blank-sass,Rocketweb-FED/magento2-theme-blank-sass,SnowdogApps/magento2-theme-blank-sass