Issue with approval of custom post type comments

I have a problem with approving comments of custom post type. Comments don’t appear in admin dashboard under “Comments” page although is written that there are pending comments and when I click to see pending comments I see message “No comments awaiting moderation.”.

This is strange because when I go to post from admin menu and click on edit, I can see all comments listed below editor, including that ones which have to be approved and I can approve them from there, but this can take a long time because I have to edit each post separately to see if there is some comments waiting to be approved.

This is how I registered post type in functions.php:

/* Custom post type: Paradise Talks */
	add_action( 'init', 'register_cpt_paradise_talks' );

	function register_cpt_paradise_talks() {

	    $labels = array(
	        'name' => _x( 'Paradise Talks', 'paradise_talks' ),
	        'singular_name' => _x( 'Talk', 'paradise_talks' ),
	        'add_new' => _x( 'Add New', 'paradise_talks' ),
	        'add_new_item' => _x( 'Add New Talk', 'paradise_talks' ),
	        'edit_item' => _x( 'Edit Talk', 'paradise_talks' ),
	        'new_item' => _x( 'New Talk', 'paradise_talks' ),
	        'view_item' => _x( 'View Talk', 'paradise_talks' ),
	        'search_items' => _x( 'Search Paradise Talks', 'paradise_talks' ),
	        'not_found' => _x( 'No talks found', 'paradise_talks' ),
	        'not_found_in_trash' => _x( 'No talks found in Trash', 'paradise_talks' ),
	        'parent_item_colon' => _x( 'Parent Talk:', 'paradise_talks' ),
	        'menu_name' => _x( 'Paradise Talks', 'paradise_talks' ),
	    );

	    $args = array(
	        'labels' => $labels,
	        'hierarchical' => false,
	        'description' => 'Your Paradise talks',
	        'supports' => array( 'title', 'editor', 'author', 'thumbnail', 'comments', 'revisions' ),

	        'public' => true,
	        'show_ui' => true,
	        'show_in_menu' => true,
	        'menu_icon' => get_bloginfo('template_url') . '/img/talks_icon.png',

	        'show_in_nav_menus' => true,
	        'publicly_queryable' => true,
	        'exclude_from_search' => false,
	        'has_archive' => true,
	        'query_var' => true,
	        'can_export' => true,
	        'rewrite' => true,
	        'capability_type' => 'post'
	    );

	    register_post_type( 'talk', $args );
	}