'Randomly' here likely corresponds to a typo in the search term.
If I type "Visual Std" instead of "Visual Stu" it goes to the Bing results.
Alternatively it shows No results if you disable Bing in the Search settings found in the top right meatballs menu.
I also would expect fuzzy search by default instead of typos sending users to Bing.
It also orrelates with missing the first letter off search terms, such as when you start typing immediately after opening the start menu