ElasticSearch: Mapping not applied to AWS ELK

while applying below mapping to my local ElasticSearch 7.4.1

private static void addIndexMapping(RestHighLevelClient client, String indexName) throws IOException {
PutMappingRequest request = new PutMappingRequest(indexName);
XContentBuilder builder = XContentFactory.jsonBuilder();
builder.startObject();
{
builder.startObject("properties");
{
builder.startObject("modifiedDate");
{
builder.field("type", "date").field("format","yyyy-MM-dd HH:mm:ss.SSS");
}
builder.endObject();
}
builder.endObject();
}
builder.endObject();
request.source(builder);
client.indices().putMapping(request, RequestOptions.DEFAULT);
}

i can see below mapping got created

{
"sandbox" : {
"mappings" : {
"modifiedDate" : {
"full_name" : "modifiedDate",
"mapping" : {
"modifiedDate" : {
"type" : "date",
"format" : "yyyy-MM-dd HH:mm:ss.SSS"
}
}
}
}
}
}

but when applying same mapping on AWS elk 7.4.2 i am seeing below mapping

{
"sandbox" : {
"mappings" : {
"modifiedDate" : {
"full_name" : "modifiedDate",
"mapping" : {
"modifiedDate" : {
"type" : "text",
"fields" : {
"keyword" : {
"type" : "keyword",
"ignore_above" : 256
}
}
}
}
}
}
}
}

In my local i have installed ElasticSearch 7.4.1 and in production ElasticSearch 7.4.2. Couldn't understand what is wrong with my code.

It seams that you create your mapping in local before inserting first document. If you don't do this, you probably are using template in your local elasticsearch. You can see more information about templates here. In your case, templates would be something look like this:

PUT _index_template/template_1
{
"index_patterns": ["te*", "bar*"],
"template": {
"settings": {
"number_of_shards": 1
},
"mappings": {
"properties": {
"modifiedDate": {
"type": "date",
"format": "yyyy-MM-dd HH:mm:ss.SSS"
}
}
}
}
}