Issue with Custom Post Types and Permalinks

I don’t recommend using category as cpt try rename it for example in product-type. For more information on category see on codex: Taxonomies

function my_custom_post_product_type() {

    $labels = array(
        'name'               => _x( 'Product Types' ),
        'singular_name'      => _x( 'Product Type' ),
        'add_new'            => _x( 'Add New' ),
        'add_new_item'       => __( 'Add New Product Type' ),
        'edit_item'          => __( 'Edit Product Type' ),
        'new_item'           => __( 'New Product Type' ),
        'all_items'          => __( 'All Product Types' ),
        'view_item'          => __( 'View Product Type' ),
        'hierarchical'       => true,
        'search_items'       => __( 'Search Product Types' ),
        'not_found'          => __( 'No Product Types found' ),
        'not_found_in_trash' => __( 'No Product Types found in the Trash' ),
        'parent_item_colon'  => '',
        'menu_name'          => 'Product Types'
    );

    $args = array(
        'labels'             => $labels,
        'description'        => 'Product Type Pages',
        'hierarchical'       => true,
        'public'             => true,
        'publicly_queryable' => true,
        'menu_position'      => 5,
        'supports'           => array( 'title', 'editor', 'thumbnail', 'excerpt', 'comments','post-formats','custom-fields','page-attributes' ),
        'has_archive'        => true,
        'can_export'         => true,
        'query_var'          => 'product-type'
    );

    register_post_type( 'product-type', $args );
}
add_action( 'init', 'my_custom_post_product_type' );