The product mentioned above has 10 variations.
What i discovered though, is that products with 0 stock, as per migration process, are allowed by WordPress to be ordered.
If in the quantity of stock, i manually take it to 1 unit, save the product and then take it back to 0 and save the product, then it is not visible and therefore cannot be ordered.
Furthermore, i update daily the stock levels through WP All Import plugin, by a csv file import. In my csv file the quantity imported is also set to 0 units for the above variations and the stock quantity is not updated as a “new” 0 quantity (like the process mentioned in the above paragraph), so people can still order products that are out of stock.
Maybe there is a way to re-index the stock levels, so WordPress can “read” them correctly?