REST API always sends "billing_issues_detected_at" subscription attribute as null

Calling /api/v1/subscriber/XXX for users who have had billing issues (for whom we receive the webhook just fine) always seems to show the “billing_issues_detected_at” attribute of the subscription as null.  Is this a known issue or is there another call we should use to find out if their cancellation was for billing reasons?

For example: below is a response for a call to one of our users who had a billing issue last year (2023).  When I look this user up on the Customers section of the RevenueCat console, it shows that they had a billing issue last year.  

{
   "request_date" : "2024-07-06T22:12:15Z",
   "request_date_ms" : 1720303935745,
   "subscriber" : {
      "entitlements" : {
         "Subscription" : {
            "expires_date" : "2023-02-11T14:14:20Z",
            "grace_period_expires_date" : null,
            "product_identifier" : "SevenMonthly",
            "purchase_date" : "2023-01-11T14:14:20Z"
         }
      },
      "first_seen" : "2023-01-04T14:13:33Z",
      "last_seen" : "2023-06-03T16:31:40Z",
      "management_url" : null,
      "non_subscriptions" : {},
      "original_app_user_id" : "$RCAnonymousID:4d3c3ebb7f0a470aa5d4d921d7263086",
      "original_application_version" : "31",
      "original_purchase_date" : "2023-01-04T14:13:17Z",
      "other_purchases" : {},
      "subscriber_attributes" : {
         "$email" : {
            "updated_at_ms" : 1672841635716,
            "value" : "xxxxx@xxxx"
         }
      },
      "subscriptions" : {
         "SevenMonthly" : {
            "auto_resume_date" : null,
            "billing_issues_detected_at" : null,
            "expires_date" : "2023-02-11T14:14:20Z",
            "grace_period_expires_date" : null,
            "is_sandbox" : false,
            "original_purchase_date" : "2023-01-04T14:14:21Z",
            "ownership_type" : "PURCHASED",
            "period_type" : "normal",
            "purchase_date" : "2023-01-11T14:14:20Z",
            "refunded_at" : null,
            "store" : "app_store",
            "store_transaction_id" : "410001421786947",
            "unsubscribe_detected_at" : "2023-04-12T06:17:09Z"
         }
      }
   }
}