Function ‘hide category’ removes my category in admin too

I have 3 categories: APP NEWS / NEWS / FEATURED I wanted to display on front-end all posts with NEWS category but also if I have 1 post with 2 categories it’s display too but with NEWS category tag. So I puted on my function file:

add_filter('get_the_terms', 'hide_categories_terms', 10, 3);
function hide_categories_terms($terms, $post_id, $taxonomy){

    // list of category slug to exclude, 
    $exclude = array('featured', 'app-news');

    if (!is_admin()) {
        foreach($terms as $key => $term){
            if($term->taxonomy == "category"){
                if(in_array($term->slug, $exclude)) unset($terms[$key]);
            }
        }
    }

    return $terms;
}

but in administration when I make a change to an article and re-register it automatically deletes the assignment to the category featured or app news, except I need it anyway. Yet I have specified ‘if (!is_admin())’, I don’t understand…

Someone have an idea please?

Have a great day!