Desactiva las variaciones agotadas que siguen permaneciendo visibles y sin opción a click https://pluginrepublic.com/display-stock-variations-unavailable-woocommerce/
function wcbv_variation_is_active( $active, $variation ) {
if( ! $variation->is_in_stock() ) {
return false;
}
return $active;
}
add_filter( 'woocommerce_variation_is_active', 'wcbv_variation_is_active', 10, 2 );