JoltTransformJSON error from NiFi, but is valid in tester

[James McMahon]

I have this JSON as flowfile content:

{
  "dates" : {
    "date_file" : "20240115184407",
    "ingested" : "20240217175748",
    "latest_date" : "19800000",
    "earliest_date" : "19800000",
    "date_info" : "YYYYMMDD"
  },
  "parents" : {
    "md5" : "86107362084b86ea64dc33dfde5e14ff",
    "sha256" :
"4ffe010f3392dddb3a880f0e60a6bf35e1e41444b7e83be0746097557d555e0f"
  },
  "triage" : {
    "filetype" : "unstructured",
    "languages" : "[\"gaelic\"]",
    "filename" : "gaelicTest.txt"
  },
  "ids" : {
    "md5" : "86107362084b86ea64dc33dfde5e14ff",
    "sha256" :
"4ffe010f3392dddb3a880f0e60a6bf35e1e41444b7e83be0746097557d555e0f",
    "sku" : "00000"
  }
}

I am trying to apply a simple JOLT transform that adds a key payload at the
same level in my json as keys dates, parents, triage, and ids.

I developed this transform - just about as simple a case you could possibly
hope for:
[
  {
    "operation": "shift",
    "spec": {
      "ids": "ids",
      "parents": "parents",
      "dates": "dates",
      "triage": "triage",
      "payload": "payload"
    }
  },
  {
    "operation": "default",
    "spec": {
      // if payload does not exist, then apply a default of null
      "payload": ""
    }
  }
]

I tested this successfully here: https://jolt-demo.appspot.com/#inception .
It works.
No big surprise - this is about as simple as it gets.

Should work in nifi, right? Can't get much easier than this.

But in nifi, it throws this error:

JoltTransformJSON[id=4d6c3f69-a72e-16b2-8cfe-2a9adb9303c7] processor
is not valid: : com.bazaarvoice.jolt.exception.SpecException: Shiftr
expected a spec of Map type, got ArrayList


Why? How can I get this to work in NiFi?