Create or Modify Ontology Form 400 issue: how to fix?

I am playing with the new(ish) feature on Ontology Manager where we can create or modify an existing object.

My workflow relies on setting values as default if the input object exists, all through overrides, and I wanted to set the new objects created with an auto-gen pk.

Unfortunately it seems like the form only works if the the pk is set by the user, which I cant really get to work the way I intend to.

Otherwise, I get these two errors:

In the ontology manager, the preview is stuck in loading and in the network logs I see (taken out the rid to make it easier on the eyes)

{
    "errorCode": "INVALID_ARGUMENT",
    "errorName": "OntologyMetadata:OntologyRidForEntityNotFound",
    "errorInstanceId": "...",
    "parameters": {
        "entityRid": {
            "type": "actionTypeRid",
            "actionTypeRid": "..."
        }
    }
}

In the workshop where I use this form an an inline action form, I get this:


  "type": "STATUS",
  "status": 400,
  "body": {
    "errorName": "Actions:ProvidedAutogeneratedObjectLocatorForInvalidParameterType",
    "errorCode": "INVALID_ARGUMENT",
    "errorInstanceId": "...",
    "parameters": {
      "actionTypeRid": "\"...\"",
      "parameterRid": "\"...\""
    }
  }
}

Do I need to this sort of workflow always via a function backed action instead?