title: ElasticSearch yields wrong results when using terms
body: <p>I have a list of documents indexed on ElasticSearch with the following structure </p>
  
  <pre><code>{
    "product_id": "xx",
    "product_desc":"some product desc"
  } 
  </code></pre>
  
  <p>When I perform a search with term, as follows, I get the correct results:  </p>
  
  <pre><code>GET my_index/my_doctype/_search
  {"query": 
   {
    "match":{"product_id": "138156"}
    }
  }
  </code></pre>
  
  <p>However, when I perform the same search with terms, I get a wrong results </p>
  
  <pre><code>GET my_index/my_doctype/_search
  {
            "query": {
              "terms": {
                "product_id": ["138156"]
          }
    }
  }
  </code></pre>
  
  <p>This happens for some products and not all them. Any ideas how to resolve this issue? </p>