Lucene query always throw not JsonObject error

[gaojianzhuang]

Describe the bug

Click the query button, always throw errors as below:
Invalid query : The node must be of type 'JsonObject'.

Actually, the query body is a json object.

{
  "query":{
    "bool":{
      "must":{
        "term":{
          "Content.ContentItem.ContentType":"Product"
        }
      },
      "filter":[
        {
          "term":{
            "Content.ContentItem.Published":"true"
          }
        }
      ]
    }
  }
}

If I removed the "filter" node, it works well.

Orchard Core version

Orchardcore: 2.1.3

To Reproduce

1. Go to '...'
2. Click on '...'
3. Scroll down to '...'
4. See error

Expected behavior

It should work with the "filter" query.

Logs and screenshots