New SubMenu Items Not Displaying

I have never had problems with other themes in regards to adding a new page, then adding the associated menu item to my Primary Menu. The new page is published and set to public. The menu displays correctly when viewing the site in admin preview mode, however, does not appear in the public site.

I am trying to add the Renko Chart Programming page. It appears in the Primary Menu under Appearance, Menus. I have added it just as I have added pages, menus for years in WP.

If I type in the url directly https://mt4programming.com/-renko-chart-programming/ the page appears and the new submenu item appears, only temporarily. Reloading the public site removes the new SubMenu item. This happens for each new page/menu I add.

I have disabled plugins one by one, nothing works.

Thank you for your assistance.