For some reason the megamenu on the not standard language disappeares when you switch to the second language with the language switcher flags. In this website Dutch is the standard language & as user you can see this megamenu.
when you switch to english, the second language here, the english megamanu is not present for a user with the dutch language as standard. Only on the off-canvas the menu is present.
It looks as if the template does'n t switch to the english version or only the megamenu of the users selected frontend language is loaded. so the megamenu is not loaded for others than the users standard.
very strange. This behavior is only present at Joomla 3, for as far as i can test..