Subscription renewals are creating orders without any product ID or variant ID values. What is going on?

It could be that you you deleted this product or variant from the Shopify admin > Products and then maybe recreated it. This caused Shopify to change the product ID and variant IDs, which means that the subscription is now set up with a product ID and variant ID, which doesn't exist anymore in your shop.
To resolve this for future renewals, it will be best to simply edit the subscription, remove the old variant from it, add the new variant to the subscription and save it.