“Visited Web Page” Filter - no results

We usually use Kentico for our landing pages, we only create Marketo landing pages for individual campaigns.

Visits to a Kentico landing page are easily recognized under the Web Activites at profile level.

But if I select “Visited Web Page” in a smart list, I don't get any results for Kentico landing pages.

Why is that and how can we change that? Or maybe I need a different filter?