When you make a change to your Beaver Builder child theme CSS, the changes may not appear for people who have visited your site unless they clear their cache.
But by changing the code in bb-theme-child/functions.php from:
add_action( 'wp_enqueue_scripts', 'FLChildTheme::enqueue_scripts', 1000 );
to:
function enqueue_bb_child_theme_style() {
wp_enqueue_style( 'fl-child-theme', FL_CHILD_THEME_URL . '/style.css', array(), wp_get_theme()->get('Version') );
}
add_action( 'wp_enqueue_scripts', 'enqueue_bb_child_theme_style', 1000 );