The following from the docs is not working, the request GET /location_cluster_ID returns an empty set of curly brances

https://developers.facebook.com/docs/marketing-api/audiences/reference/basic-targeting/#location

Target Zip Code, See targeting search API. Limit: 50,000. Formerly 2,500. If you provide more than 2,500 we create an array known as location_cluster which represents a set of zip codes. Example: 'zips':[{'key':'US:94304'},{'key':'US:00501'}]

To read a location_cluster and see the locations targeted: GET /location_cluster_ID

Debug info

==== Query
  curl -i -X GET \
   "https://graph.facebook.com/v19.0/7376329959133698?fields=locations%2Cid&access_token=<access token sanitized>"
==== Access Token Info
  {
    "perms": [
      "ads_management"
    ],
    "user_id": XXX,
    "app_id": XXX
  }
==== Parameters
- Query Parameters


  {
    "fields": "locations,id"
  }
- POST Parameters


  {}
==== Response
  {
    "__debug__": {}
  }
==== Debug Information from Graph API Explorer
- https://developers.facebook.com/tools/explorer/196077369933780/?method=GET&path=7376329959133698%3Ffields%3Dlocations%2Cid&version=v19.0