When using requesting milestone id, return result is null and error

[brettski]

When querying an event and asking for milestones, if the id is included in the query the milestone results are null with error.

Query without id:

  query getEvent {
    events {
      event(id: "ByE7Dc7eCGcRFzLhWhuI") {
        get {
          name
          milestones {
            title
            description
            dueDate
          }
        }
      }
    }
  }

Result

  "data": {
    "events": {
      "event": {
        "get": {
          "name": "THAT Conference",
          "milestones": [
            {
              "title": "Call for Sponsors",
              "description": null,
              "dueDate": "2019-11-01T00:00:00.000Z"
            },
---- snip ----
            {
              "title": "Pre-Conference",
              "description": null,
              "dueDate": "2020-08-03T00:00:00.000Z"
            },
            {
              "title": "THAT Conference 2020",
              "description": null,
              "dueDate": "2020-08-04T00:00:00.000Z"
            }
          ]
        }
      }
    }
  }
}

Query with id:

  query getEvent {
    events {
      event(id: "ByE7Dc7eCGcRFzLhWhuI") {
        get {
          name
          milestones {
            id
            title
            description
            dueDate
          }
        }
      }
    }
  }

error:

{
  "errors": [
    {
      "message": "Cannot return null for non-nullable field Milestone.id.",
      "path": [
        "events",
        "event",
        "get",
        "milestones",
        0,
        "id"
      ],
      "extensions": {
        "code": "INTERNAL_SERVER_ERROR",
        "serviceName": "Events",
        "query": "{events{event(id:\"ByE7Dc7eCGcRFzLhWhuI\"){get{name milestones{id title description dueDate}}}}}",
        "variables": {}
      }
    },
    {

When milestone id is requested with other collection it appears to return a null for each milestone value.