A few issues with the avada mobile menu:
Either the menu doesn’t dropdown the links at all or it drops them but the menu is pulled back up instantly.
I’ve tried to install some custom mobile menu plugins but they don’t look that good.
An easy fix was to go to the avada settings and enable from AVADA theme options > advanced > Enable JS Compiler (SET TO ON).
This has fixed the issue with the menu.
I’ve tested it and it works perfect on 5 browsers, Firefox, Chrome, Edge, IE, Safari and on Android and iPhone.