Random websites get recommended on private mode

I (almost) always use the safari private mode, and if not I delete the history frequently. My problem is that always when I search up something, there comes National Geographic kids as bookmarks and history, even though both is empty. Later on I get even more kids websites that I have never visited before popping up as recommended. This is private mode and my history and bookmarks are empty. These are all official websites and no virus, but it’s still pretty annoying.