Issue with invalid variants not disabling add to cart button

[Viewsofjavi]

Seems that the code changed to “selected, first available or default” variant selection for the add-to-cart/buy button functionality. Instead of checking availability OR variant configuration for the selected combination, the add-to-cart/buy buttons allow the customer to add the default variant to their cart when they select an unconfigured variant. I had shopify support help me, it wasn’t to do with the theme. Problem persisted with different themes. The swatches are configured correctly, switching to dropdowns changed nothing. An unconfigured variant selection shouldn’t allow the customer to add anything to the cart. I don’t know when the code changed but there’s another seller I’ve come across with the same issue and they didn’t attempt to integrate FB/Instagram.