Required not working with Gutenberg

Hello,

I just noticed that fields that are required stop working when using Gutenberg, once Classic editor is enabled the required functionality works again.

I tried with this sample metabox.

function your_prefix_get_meta_box( $meta_boxes ) {
    $prefix = 'prefix-';

    $meta_boxes[] = array(
        'id' => 'untitled',
        'title' => esc_html__( 'Untitled Metabox', 'metabox-online-generator' ),
        'post_types' => array('post', 'page' ),
        'context' => 'advanced',
        'priority' => 'default',
        'autosave' => 'false',
        'fields' => array(
            array(
                'id' => $prefix . 'text_1',
                'type' => 'text',
                'name' => esc_html__( 'Text', 'metabox-online-generator' ),
                'attributes' => array(
                    'required' => 'true',
                ),
            ),
        ),
    );

    return $meta_boxes;
}
add_filter( 'rwmb_meta_boxes', 'your_prefix_get_meta_box' );