### Elasticsearch Version

8.2.0

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

docker-image = docker.elastic.co/elasticsearch/elasticsearch:8.2.0

### Problem Description

We are trying to migrate from Elasticsearch 6.7.1 to Elasticsearch 8.2.0.

With the same amount of documents per bulk request (100 docs per request), we always get a socket timeout in Elasticsearch 8.2.0. Everything works fine in Elasticsearch 6.7.1.

I noticed that indexing the same document in Elasticsearch 8.2.0 takes 44152ms. In Elasticsearch 6.7.1, indexing takes 50ms.

### Steps to Reproduce

[elasticsearch_8.2.0.txt](https://github.com/elastic/elasticsearch/files/8754299/elasticsearch_8.2.0.txt)
[elasticsearch_6.7.1.txt](https://github.com/elastic/elasticsearch/files/8754300/elasticsearch_6.7.1.txt)



### Logs (if relevant)

_No response_
server/src/test/java/org/elasticsearch/index/mapper/CopyToMapperTests.java
.field("gte", "2019-11-10T01:00:00.000Z")
                .field("lt", "2019-11-11T01:00:00.000Z")
                .endObject()
                .endObject()
        );
        MapperParsingException ex = expectThrows(
            MapperParsingException.class,
            () -> docMapper.parse(new SourceToParse("1", json, XContentType.JSON)).rootDoc()
        );
        assertEquals(
            "Cannot copy field [date] to fields [date_copy]. Copy-to currently only works for value-type fields, not objects.",
            ex.getMessage()
        );
    }
    public void testCopyToWithNullValue() throws Exception {
        DocumentMapper docMapper = createDocumentMapper(
            topMapping(
                b -> b.startObject("properties")
                    .startObject("keyword_copy")
                    .field("type", "keyword")
                    .field("null_value", "default-value")
                    .endObject()
                    .startObject("keyword")
                    .field("type", "keyword")
                    .array("copy_to", "keyword_copy")
                    .endObject()
                    .endObject()
            )
        );
        BytesReference json = BytesReference.bytes(jsonBuilder().startObject().nullField("keyword").endObject());