[BUG] OpenSearchException: Request failed: [mapper_parsing_exception] failed to parse

What is the bug?

When we push the document as a JSON string using IndexRequest, the API fails with the below error the same works if we pass the document as a java map.
Caused by: org.opensearch.client.opensearch._types.OpenSearchException: Request failed: [mapper_parsing_exception] failed to parse
at org.opensearch.client.transport.aws.AwsSdk2Transport.parseResponse(AwsSdk2Transport.java:530)
at org.opensearch.client.transport.aws.AwsSdk2Transport.executeSync(AwsSdk2Transport.java:438)
at org.opensearch.client.transport.aws.AwsSdk2Transport.performRequest(AwsSdk2Transport.java:241)
at org.opensearch.client.opensearch.OpenSearchClient.index(OpenSearchClient.java:764)

Are there any working examples where JSON string is pushed as a document instead of java POJOs?

I'm trying this in Scala.

val openSearchClient: OpenSearchClient = new OpenSearchClient(
   new AwsSdk2Transport(httpClient,
                        host,
                        "aoss",
                        region,
                        AwsSdk2TransportOptions.builder().setCredentials(credentials).build()))
 val documentJsonStr                    = "{'name': 'yashwanth', 'age': '23'}"
 val documentJson                       = JsonData.of[String](documentJsonStr)
 val request                            = IndexRequest.of[JsonData](f => f.index(index).document(documentJson))
 openSearchClient.index(request)

Below code works, where the document is passed as java map to the same index

  val openSearchClient: OpenSearchClient = new OpenSearchClient(
    new AwsSdk2Transport(httpClient,
      host,
      "aoss",
      region,
      AwsSdk2TransportOptions.builder().setCredentials(credentials).build()))
  val temp2 = new util.HashMap[String, String]()
  temp2.put("name", "yashwanth")
  temp2.put("age", "23")

  val documentIndexRequest =
    new IndexRequest.Builder().id("1").index(index).document(temp2).build

  openSearchClient.index(documentIndexRequest)

Start with the IndexRequest.document call and inspect JsonData.of[String], then trace the request through OpenSearchClient.index and AwsSdk2Transport. Reproduce the Scala JSON-string example alongside the working HashMap example; done should identify why the document forms differ and provide a verified usage path or a clearly scoped client fix.