Problem with ingest node pipeline setup - java.lang.Integer cannot be cast to class java.lang.Long

Hi there,

I was trying to use es(6.5) ingest node pipeline (instead of logstash) to extract info from filebeat (6.5) logs, however my pipeline (as following) seemed not work in simulation.

POST _ingest/pipeline/_simulate
{
  "pipeline" :
  {
    "description": "_description",
    "processors": [
      {
        "set": {
          "field": "foo2",
          "value": "bar2"
        }
      }
    ]
  },
  "docs": [
    {
      "_index": "prod-main-2019.01.31",
      "_type": "doc",
      "_id": "DOK-omgBXfHd0GoqVXXP",
      "_version": 1,
      "_score": null,
      "_source": {
        "foo": "bar"}
    }
  ]
}

the response is

{
  "error": {
    "root_cause": [
      {
        "type": "class_cast_exception",
        "reason": "class java.lang.Integer cannot be cast to class java.lang.Long (java.lang.Integer and java.lang.Long are in module java.base of loader 'bootstrap')"
      }
    ],
    "type": "class_cast_exception",
    "reason": "class java.lang.Integer cannot be cast to class java.lang.Long (java.lang.Integer and java.lang.Long are in module java.base of loader 'bootstrap')"
  },
  "status": 500
}

This problem might be caused by the field "_version": 1,, how I could solve it? Thanks!

pls kindly let me know if someone manage to get correct response of the pipeline simulation. thanks!