You're talking about the option disabled in the variant selection right? Since the add to cart button is checked using the checkAvailability function. But you're right, if the individual variants are disabled only happens at build time. But I figured since a rebuild should happen anyways when product inventory changes its not worth the extra code to handle this case. But of course it would be better if it were handled, especially with stores of high traffic. I'm happily merging any PR's ;).