Starting from version 2.8 menu css is broken

Hi everybody.
I’m using a child theme built with Child Theme Configurator plugin, but maybe I did something wrong because starting from version 2.8.0, when Neve gets an update, all my menus are broken: they are displayed as block, and the dropdown menu is not hidden as it should be (see the link). Even in the customizer, all controls to customize the menus in the sidebar are no more ordered within tabs but just displayed in one column…

I have already deactivated all my plugins (but Elementor) with no success.

The issue appears both on Linux and on Windows systems, using Firefox, Chrome and Edge.

Looking at developer tools, It looks like a lot of css is just missing.

I can’t post a live link because in the live website I periodically downgrade to version 2.7.7 and development website is in my local environment.

I’d be happy even with a suggestion about how can I prevent parent theme updates affect my child theme ??
Thank you!

The page I need help with: [log in to see the link]