### 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
private final String key;
        private final IndexOrdinalsFieldData delegate;
        private final ToScriptFieldFactory<SortedSetDocValues> toScriptFieldFactory;
        private KeyedFlattenedFieldData(
            String key,
            IndexOrdinalsFieldData delegate,
            ToScriptFieldFactory<SortedSetDocValues> toScriptFieldFactory
        ) {
            this.delegate = delegate;
            this.key = key;
            this.toScriptFieldFactory = toScriptFieldFactory;
        }
        public String getKey() {
            return key;