Total Hits in elastic Search prepareSearch() behaves in an inconsistent manner

Elastic Stack Elasticsearch
15

MatchPhrase too cant help. Again inconsistent results some times 28, sometimes 10.
please find the response below.

{
"took": 0,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": 22,
"max_score": 0.021978907,
"hits": [..........]
}
}

I'm using reactive pattern. Does it make any difference?

Observable.create(new OnSubscribe<List<InnerSearchHits>>() {
@Override
public void call(Subscriber<? super List<InnerSearchHits>> t) {

			QueryBuilder queryBuilder = QueryBuilders.matchPhraseQuery(filterKey,filterValue);
			ListenableActionFuture<SearchResponse> f = esClient.getESClient().prepareSearch(index)
            .setQuery(queryBuilder).
            setFrom(0)
            .setSize(10000)
            .execute();
			Observable.from(f).map(x -> {
				List<InnerSearchHits<E>> innerSearchHits = new ArrayList<InnerSearchHits<E>>();
    			SearchHits hits = x.getHits();
    		
    			for (SearchHit searchHit : hits) {
    		.............
				}
                return innerSearchHits;
			}).onErrorReturn(e -> {      			
				......
        		return null;
			}).subscribe(...
				}
			}, e -> { 
				if (!t.isUnsubscribed()) {
					t.onError(e);
				}
			}, () -> {
				if (!t.isUnsubscribed()) {
					t.onCompleted();
				}
			});
			
		}
	});

Same code is working fine, if I do remote debugging