How to disable default category linkbuilding?

If you’re using pretty permalinks – which you are, with this type of URL – WordPress will automatically try to figure out any URL that you type in.

In your example URL, “company” is the slug. So, when you type in example.com/company, WordPress uses that slug to figure out “Okay, I only see one post with the slug ‘company,’ and that one is a subpage of ‘products,’ so I’ll send them there.”

WP does redirect rather than just displaying the page at that URL, so you shouldn’t run into issues with search engines indexing the shorter URLs. If you want to be doubly certain, make sure you have canonical URLs set (such as by using an SEO plugin, or a theme that adds them for you) to tell search engines the long URL is the desired one, and don’t link to the short version.