[Theme: Bose] – How to fix an implode error?

Hi there!

I’ve just installed the Bose template and also created a child theme for it. However, the following error message appears on the center of my website:

Warning: implode(): Invalid arguments passed in /home/hello582/public_html/teste/wp-content/themes/bose/featured.php on line 12

(if you prefer, have a look at the picture: https://s28.postimg.org/wtvvy8m99/Capture.png )

I haven’t changed anything on the child theme, so the existing child theme code is still the original one:

<?php
//
// Recommended way to include parent theme styles.
//  (Please see https://codex.www.ads-software.com/Child_Themes#How_to_Create_a_Child_Theme)
//
add_action( 'wp_enqueue_scripts', 'theme_enqueue_styles' );
function theme_enqueue_styles() {
    wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );
    wp_enqueue_style( 'child-style',
        get_stylesheet_directory_uri() . '/style.css',
        array('parent-style')
    );
}
//
// Your code goes below
//

I’m a very beginner at websites creation, so I haven’t got any clue about what the problem is. Could anyone help me?

Thanks a lot!

[Moderator Note: No bumping, thank you.]