Remove Custom Sidebars inheritance for child pages [ if you improve this solution, please, let me know :) ]

namespace_remove_inherited_sidebars.php

<?php
/**
 * Remove Custom Sidebars inheritance for child pages
 * 
 * The issue is described at the following link
 * @link https://wordpress.org/support/topic/option-to-remove-inheritance
 */
 
function namespace_remove_inherited_sidebars( $replacements ) {
	global $post;

	if ( $post->post_parent != 0 && count($replacements) > 0 ) {

		$post_id = $post->ID;
		$post_meta = get_post_meta( $post_id, '_cs_replacements', true );

		if ( ! is_array( $post_meta ) ) {
			$post_meta = array();
		}

		if( empty($post_meta) ) {

			return false;

		} else {

			foreach ($replacements as $key => $value) {

				if ( empty($post_meta[$key]) ) {
					unset($replacements[$key]);
				}

			}

		}
	}
	
	return $replacements;
}
add_filter( 'cs_replace_sidebars', 'namespace_remove_inherited_sidebars' );

?>