Your hunch about something is wrong in header.php is correct. I found the bug. Please read this thread for explanation. https://theme4press.com/support/topic/menu-hover-effect-not-working-in-my-1-9-0-evolve/page/2/#post-19881
You may want to remove the unnecessary custom css codes provided to fix the boxed layout.
I did not log into your WordPress admin to do any modification.
If you need my help, Please give me a shout, if not, it’s fine with me if you prefer to keep your custom css modifications.
For your information, In version 2.0.0, We only replace the Theme Options to use Redux Framework, we did not modify any design layout. Version 2.0.1 is a bug fix version.