Thank you for reporting this issue.
I've managed to reproduce the problem locally. The problem appears after default products type fields are changed. In this case after Title field is changed, all new products are created with empty titles no matter if they are filled out. Unfortunately, the only workaround which I can suggest you is to re-create the ’Shippable Books’ product type without changing Title field and, then re-create the products.
I logged this issue with high priority and, forwarded for fixing. I created a PITS issue. You can follow the PITS Issue by its ID: 8690 .
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