Sale is never finished when product has supply on sale and is not purchasable nor producible.
We found a sale, that was never marked as done because it has a product that has the supply on sale value set to 'always' but is not purchasable nor producible. On such case no purchase request not production is created for the product but the sale is never updated, but the considers it as supply on sale with supply state blank (so not submitted).
I'm not sure if we should update the code to ignore such corner case or to forbid the user to remove the purchasable or producible flag from a product that has supply on sale.