REST API and shortcodes

I’m using this great plugin for my project and now I need to make it work with a mobile app via REST API.

It works but shortcodes won’t be decoded. I tried the following snippet to do this:

add_action( 'rest_api_init', function ()
{
    register_rest_field(
		'page',
		'content',
		array(
				'get_callback'    => 'sff_do_shortcodes',
				'update_callback' => null,
				'schema'          => null,
		)
	);
    register_rest_field(
		'event',
		'content',
		array(
				'get_callback'    => 'sff_do_shortcodes',
				'update_callback' => null,
				'schema'          => null,
		)
	);
});

function sff_do_shortcodes( $object, $field_name, $request )
{
   WPBMap::addAllMappedShortcodes(); // This does all the work

   global $post;
   $post = get_post ($object['id']);
   $output['rendered'] = apply_filters( 'the_content', $post->post_content );

   return $output;
}

…and it works for pages and posts, but not for events.
Please help!