Filter Products by Attribute not displaying all options

I’m using the Filter Products by Attribute widget in the shop sidebar. All products have a product_type attribute assigned. However on the linked URL, the filter is only showing 2 products across two attributes. It should be displaying 5 products across 4 “product-types”.
It appears that the three missing products all have product variations based on separate attributes.
How do I get the filter to still show these?

The page I need help with: [log in to see the link]