Backlinks have to do with links made in other notes, and pay no heed to where files are in the filesystem. They aren’t generated automatically from the file/folder hierarchy, like the links in my screenshot are.
In my system, when notes are moved from one filesystem folder to another, their cards will disappear from the old location and reappear in the new one. And subnotes don’t have to link to their parent. Even if I made Inquisitive field an empty note with no link or mention of Field, it would still appear as a card when I visit Field.