WooCommerce: Bulk Quantity in Cart

Problem is on cart page has_term is false because it is checking if cart page have terms 12-pack or 6-pack. You also need to provide post object/ID to has_term() as a third parameter.

Updated code:-

function input_set_all_values( $args, $product ) { 
    if (( has_term('6-pack', 'criteria', $product->post ) ) ) {
        $args['step'] = 6;
        $args['min_value'] = 6;
        return $args;
    } else if (( has_term('12-pack', 'criteria', $product->post ) ) ) {
        $args['step'] = 12;
        $args['min_value'] = 12;
        return $args;
    } else {
        $args['step'] = 1;
        $args['min_value'] = 1;
        return $args;
    }
}