FB payment object without user field

Question

Is anybody knows why the Graph response for Payment Object can be without field user?

I'm trying to make this query:

https://graph.facebook.com/PAYMENT_ID?fields=id,user,items,application&access_token=APP_ACCESS_TOKEN

where PAYMENT_ID is correct id, APP_ACCESS_TOKEN is correct token

And I receive this:

{
   "id": PAYMENT_ID,
   "application": {
      "category": "Games",
      "link": PAYMENT_APP_LINK,
      "name": PAYMENT_APP_LINK,
      "namespace": PAYMENT_APP_NAMESPACE,
      "id": PAYMENT_APP_ID
   },
   "items": [
      {
         "type": "IN_APP_PURCHASE",
         "product": PAYMENT_PRODUCT_ITEM_LINK,
         "quantity": 1
      }
   ]
}

where PAYMENT_* - correct values, they are hidden for secure reason. I've tried with api version: v2.5, v2.6, v2.7, v2.8

This is not happens with all my payments, just with a bit of them.

I have only one idea why this happen - user has deleted my app right after purchase (WTF?). But any way - Facebook should store and provide complete data about payment object.

BTW: I've searched all question that tagged: [facebook-payments] or [facebook] and [payments].

Answer 1

I've received response from FB Support Team and want to share it with you, dear stackoverflow user.

It can happen, when user de-activates their Facebook account. For more information you can check it: https://developers.facebook.com/docs/games_payments/fulfillment

But, there are other undocumented reasons such as when a user blocks the app or is disabled by Facebook Security Teams.

Summarize: Please make sure that your code is built to handle null or empty values for this property.