Hi Luoy,
Thanks for responding.
I have attached five images, as follows:
1. Attribute setup.
2. Attribute assignment to a product (proving the system is treating the attribute normally in some cases).
3. A screenshot of custom field controls, which includes the original 3 attributes, but not customer-signature-product.
4. The WooCommerce Views screen. I have no idea if this has any bearing on this issue, but I did run the Calculate Product Attributes for Views Filters process at the bottom, both after I created the first 3 attributes and after I created the customer-signature-product.
5. A screenshot of all my installed plugins.
Also, I'm on a Bitnami WAMP local install using WP 3.9.1. Toolset Bootstrap 1.2 is my base theme. I do use a child theme, but it does not touch attributes or products in any way.
Let me know if you need anything else,
Wayne