Category Order

I don’t understand what is happening here.
I’ve got 3 existing categories with multiple sub categories under them and thousands of products within those sub categories. I created the fourth category and dragged it down to the bottom. I created a sub category under it and added a product. But it’s appearing as the first category on the home page. Even though the order is showing as it’s down the bottom, when you create a sub category and choose the parent for it the main category is showing up the top, not in the right order. I’ve deleted everything multiple times now, cleared my cache, rebooted the laptop and just tried again. Same thing.
Does anyone have any idea what is going on and how I can fix it?