meta_box_cb bug demo

meta_box_cb-bug-demo.php

<?php
/**
 * Plugin Name: TIVWP Demo 28033
 * Plugin URI: https://gist.github.com/tivnet/c99265e4884f7df5cb0f
 * Description: Demonstrates WP bug <a href="https://core.trac.wordpress.org/ticket/28033">#28033</a>
 * Version: 14.11.02
 * Author: TIV.NET
 * Author URI: http://www.tiv.net
 * License: GPL2
 * Copyright 2014 Gregory Karpinsky (tiv.net), All Rights Reserved
 */

add_action( 'init',
	function () {
		register_post_type( 'test_cpt',
			[
				'labels' => [
					'name' => 'Test CPT'
				],
				'public' => true,
			]
		);
		register_taxonomy( 'test_tax', 'test_cpt',
			[
				'labels'      => [
					'name' => 'Test TAX'
				],
				/**
				 * This causes the bug
				 */
				'meta_box_cb' => 'post_categories_meta_box',
				/**
				 * This is a possible workaround - uncomment to see
				 */
				// 'meta_box_cb' => 'single_taxonomy_select_meta_box',
			]
		);
	}
);

/**
 * Meta box to select only one taxonomy value
 *
 * @param WP_Post $post
 * @param array   $box
 */
function single_taxonomy_select_meta_box( WP_Post $post, Array $box ) {

	$taxonomy = $box['args']['taxonomy'];

	$term_name_of_the_current_post = wp_get_object_terms( $post->ID, $taxonomy, [ 'fields' => 'names' ] )[0];

	$all_term_names = get_terms( $taxonomy, [ 'fields' => 'names', 'hide_empty' => false ] );
	?>
	<label>
		<?php esc_html_e( 'Please choose:' ); ?>
		<select name="tax_input[<?php echo esc_attr( $taxonomy ); ?>]">
			<?php foreach ( $all_term_names as $term_name ) : ?>
				<option <?php selected( $term_name_of_the_current_post, $term_name ); ?>>
					<?php echo esc_html( $term_name ); ?>
				</option>
			<?php endforeach; ?>
		</select>
	</label>
<?php
}