I have the following page structure /insights/agenda/topics/ same on the menu too and I use the pretty permalinks.
If I view the page, it returns a 404 error. I manage to view the page when I used the plain permalinks. Also if I move this page to another path, like /about-us/what-we-do/topics/ it also works.
There is no other page with the same name/slug, there is nothing in the trash. I flashed the permalinks multiple times and I also tried to create a new page and add it in the hierarchy as a 3rd level page and still got a 404. However there is a page called 'agenda' and a custom content type with the same name.
The only relative to this is a Custom Content Type and a Custom Taxonomy for that called 'topic' and 'trending_topic' respectively. They suppose to list them on this 3rd level page.
What do I miss? Can somebody point me to the right direction?