Incorrect Top Menu Displayed

Hi,

I would like to change the default menu to a specific one for the help centre.
When I open the help center page in WordPress to edit and change the menu, it doesn’t work at least fort the main page of the help centre (it works for article) so for this page, I need to hide the menu.

My website in staging: https://staging2.textografo.com/help-center/

Any idea how to solve that?

https://wordpress.org/plugins/wp-knowledgebase/