Why do some Facebook posts from a private group not contain a message field?

The results I get from the Facebook Graph API (all supported versions) on a private FB group differs from what I see when I go to the actual Facebook website. Some of the posts from the private Group's /feed don't contain information such as the "message" property for some reason, even though I can see it on the website.

From Facebook.com:

Christine : Can't go anymore! Selling last minute Front Orchestra tickets to the ...

Ingrid : For Sale: Portable booster seat high chair $20 — Pick up at ...

From the Graph API:

[{
      ...
      "message": "Can't go anymore! Selling last minute Front Orchestra tickets to the ...", 

     "privacy": {
        "value": "", 
        "description": "", 
        "friends": "", 
        "allow": "", 
        "deny": ""
      }, 
      "type": "status", 
      "created_time": "2015-04-19T00:07:11+0000", 
      "updated_time": "2015-04-19T04:44:49+0000", 
      "is_hidden": false, 
      ...

    }, 
    {
      "privacy": {
        "value": "", 
        "description": "", 
        "friends": "", 
        "allow": "", 
        "deny": ""
      }, 
      "type": "status", 
      "created_time": "2015-04-16T22:11:36+0000", 
      "updated_time": "2015-04-19T04:41:01+0000", 
      "is_hidden": false, 
      ...
    }]

You will notice that there is only a "message" field in the first post, and not in the second -- although, I don't see any reason that this should be happening.

FYI, I get the same information if I get the post details by fetching the ID of the incomplete post from the graph api.