无法访问评论元？

The Setup

Using the Reviews extension for WP Job Manager, I have comments with the meta field review_average which is an average of `review_stars. I'm customizing the WP REST API so I can read and write comments remotely via the mobile app I'm building.

I've exposed these fields with

 register_meta( 'comment', 'review_average', array( 'show_in_rest' => true, 
                                                'type' => 'string',
                                                'description' => 'review_average',
                                                'single'=> false));
 register_meta( 'comment', 'review_stars', array( 'show_in_rest' => true, 
                                                'type' => 'string',
                                                'description' => 'review_stars',
                                                'single'=> false));

which results in this field in the REST API response for comments:

meta: {
  review_average: [
    "4"
  ],
  review_stars: [
    "Array"
  ]
},

(I can't seem to break down that array, but there's only one stars category so the average is fine)

I've written a create_review function that uses add_comment_meta to write to review_average and review_stars which successfully gives the comment the right stars. Both those meta values are required for it to work.

function create_review($param) {
  $id = wp_insert_comment(array('comment_post_ID'       => $param['post_id'],
                                'comment_author'        => $param['username'],
                                'comment_author_email'  => $param['email'],
                                'user_id'               => $param['user_id'],
                                'comment_content'       => $param['content']));

  if ($id) add_comment_meta($id, 'review_average', $param['rating']); 
  if ($id) add_comment_meta($id, 'review_stars', array('Your Rating'=>$param['rating'])); 

  return get_comment($id);
}

The Problem

I can't seem to get the ratings meta info into a response for the comments. On my way to writing the "index" function get_comments, I've written the "show" function, get_commment:

function get_review($param) {
  $id = $param['id'];
  $info = get_comment($id);
  $res = array( 
    'id' => $id,
    'author_name' => $info->comment_author,
    'author_email' => $info->comment_author_email,
    'author_id' => $info->user_id,
    'date' => $info->comment_date,
    'rating' => $info->review_average
  );
  return $res;
}

The response has rating: null. Same result with 'rating' => $info->meta->review_average, as well as using _review_average in both those scenarios.

I have another function for my custom posts, which are job_listings that in my app are customers.job_listing has a meta field that shows up in the default REST API response under meta as _job_location, but inside my get_customer function, $res['address'] = $info->_job_location; works just fine!

How do I get the damn rating_average meta!?

Well, 'rating' => get_comment_meta($id) inside my get_review method gives me this:

"rating": {
        "review_average": [
            "4"
        ],
        "review_stars": [
            "a:1:{s:11:\"Your Rating\";s:1:\"4\";}"
        ]
    }

And then

'rating' => get_comment_meta($id)['review_average'][0],
'rating_info' => get_comment_meta($id),

Gives me a nice full

"rating": "4",
    "rating_info": {
        "review_average": [
            "4"
        ],
        "review_stars": [
            "a:1:{s:11:\"Your Rating\";s:1:\"4\";}"
        ]
    }

I'm learning php as I go, so I'd love if someone could post a comment about why

get_comment_meta($id)->review_average

returns null but

get_comment_meta($id)['review_average']

works.