Product page not showing all available options. Bug?

My client has set the quantity available to infinite for all products and product variations, yet when you first go to this page,, the defaults are color: white, size: small. If you click on size it shows no other options for size. If you then change the color to grey, all sizes are available. Then if you switch back to white, all sizes are available. But obviously this is a bit of a problem as the customer wouldn’t know that unless they switched colors back and forth.