Json_parse_exception during ES 1.3.9 to 5.2.1 reindex from remote

[Tyler_Dockstader]

Sorry if this is the wrong place to ask this question, I am trying to reindex from remote cluster (described here https://www.elastic.co/guide/en/elasticsearch/reference/current/reindex-upgrade.html#reindex-upgrade-remote)

All works fine but after a few minutes I get the following error. Is there any way around this like skipping invalid documents?

curl -XPOST 'localhost:9200/_reindex?pretty' -H 'Content-Type: application/json' -d'
{
  "source": {
    "remote": {
      "host": "http://<old-es-box>:9200"
    },
    "index": "old_index"
  },
  "dest": {
    "index": "new_index"
  }
}
'

{
  "error" : {
    "root_cause" : [
      {
        "type" : "parsing_exception",
        "reason" : "[hits] failed to parse field [hits]",
        "line" : 1,
        "col" : 1074329
      }
    ],
    "type" : "parsing_exception",
    "reason" : "[search_response] failed to parse field [hits]",
    "line" : 1,
    "col" : 1074329,
    "caused_by" : {
      "type" : "parsing_exception",
      "reason" : "[hits] failed to parse field [hits]",
      "line" : 1,
      "col" : 1074329,
      "caused_by" : {
        "type" : "json_parse_exception",
        "reason" : "Illegal character ((CTRL-CHAR, code 0)): only regular white space (\\r, \\n, \\t) is allowed between tokens\n at [Source: org.apache.http.nio.entity.ContentInputStream@98e46cb; line: 1, column: 1074331]"
      }
    }
  },
  "status" : 400
}

Thanks!