Strange behaviour of the side with new page builder elementor

Hey all together,

i have a very spooky problem with a friends homepage.
She has changed the page builder plugin from Visual Composer to Elementor and recreated the pages with Elementor.
But when we load the side and click on one of the menue points, the old design is still shown, only when i load the relevant side again manually by clicking in the browsers URL field the new elementor created design is shown … Does anyone have an idea what this phenomenon is about? Is it a problem with Elementor or with the Theme (brigde) or WP?
I have erased all the old pages and also checked to clear cookies and stuff but the problem remains.

Thanks a lot for help

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