cmb2 user meta object_id issue

cmb2-functions.php

<?php
//issue: cmb2 metabox form getting wrong object_id for user edit form, so it's can't display the meta values stored in database.
//cmb2 veriosn 2.2.1
add_action( 'cmb2_init', 'UserMetabox' );
function UserMetabox(){
	$cmb_user_fields = new_cmb2_box( array(
			'id'               => '_user_info',
			'title'            => 'User Extras',
			'object_types'     => array( 'user' ), // Tells CMB2 to use user_meta vs post_meta
			'show_names'       => true,
			//'new_user_section' => 'add-existing-user',
	) );

	$cmb_user_fields->add_field( array(
			'name'    => 'Avatar',,
			'desc'    => 'Upload Avatar image. if not upload default Avatar will be your Gravatar Avatar',
			'id'      => '_user_avatar',
			'type'    => 'file',
			'allow' => array('attachment' ),
			'options' => array(
					'url' => false,
					'add_upload_file_text' => 'Add Image'
			),
			'preview_size' => array( 150, 150 ),
	) );
}