XContentType.Json not working

IndexRequest iRequest = new IndexRequest(LoadBalancerVip+"9" , "_doc");
iRequest.source(flattenedJson,XContentType.JSON);
This innocent XContentType.Json cannot insert more than 150 records neither it shows any bug try at your end.
JVM usage disk usage are normal. Once I remove XContentType.json it works perfectly fine.
Just incase if this helps someone
Data to try
{"A":true,"B":"BVALUE","name":"Joe","C":"#C:ID","Key":29,"MYAddress":"11.11.111.0","from":"google.com"}"
type or paste code here

It's not really clear what your problem is here sorry, as it's very hard to follow your post. Please consider editing it and making things clearer.