Error on product page

I have created a group for product variations sharing the same stock.
https://ibb.co/JwLGmPfh
https://ibb.co/3mR5mCDk
I have enabled the ‘quantity stock’ visibile on the product page, in woocommerce settings.
Quantity 10 with backorders allowed inside your plugin settings.

Results on the product page:
The quantity is not showing
Appear ‘Available on backorder’ but it is not true, because the quantity is 10 and the product is in stock.