### Elasticsearch Version

8.8.0-SNAPSHOT

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

MacOS

### Problem Description

API when called is returning invalid response, on the same data terms aggs query runs fine 

![image](https://user-images.githubusercontent.com/3505601/220749805-ddf0d735-60d5-4e45-85bf-941ea3076a3f.png)


When run as aggs query 

![image](https://user-images.githubusercontent.com/3505601/220764360-49f7b648-8b15-43cf-afe2-01bd62e8ebc5.png)


### Steps to Reproduce

Queries are mentioned above ^^

### Logs (if relevant)

_No response_
server/src/main/java/org/elasticsearch/index/mapper/flattened/FlattenedFieldMapper.java
}
        @Override
        public int docFreq() throws IOException {
            return delegate.docFreq();
        }
        
        @Override
        public AttributeSource attributes() {
            throw new UnsupportedOperationException();
        }
        @Override
        public boolean seekExact(BytesRef text) throws IOException {
            throw new UnsupportedOperationException();
        }
        @Override
        public SeekStatus seekCeil(BytesRef text) throws IOException {
            throw new UnsupportedOperationException();
        }
        @Override
        public void seekExact(long ord) throws IOException {
            throw new UnsupportedOperationException();
        }
        @Override
        public void seekExact(BytesRef term, TermState state) throws IOException {
            throw new UnsupportedOperationException();
        }
        @Override
        public long ord() throws IOException {
            throw new UnsupportedOperationException();
        }