Fails reproducible for me on master:

```
./gradlew ':server:internalClusterTest' --tests "org.elasticsearch.search.aggregations.bucket.RandomSamplerIT.testRandomSamplerHistogram" -Dtests.seed=E53385B3A635A5D7 -Dtests.locale=nn-NO -Dtests.timezone=Asia/Rangoon -Druntime.java=18
```

ends in 

```
  2> REPRODUCE WITH: ./gradlew ':server:internalClusterTest' --tests "org.elasticsearch.search.aggregations.bucket.RandomSamplerIT.testRandomSamplerHistogram" -Dtests.seed=E53385B3A635A5D7 -Dtests.locale=nn-NO -Dtests.timezone=Asia/Rangoon -Druntime.java=18
  2> java.lang.NullPointerException: Cannot invoke "java.lang.Double.doubleValue()" because the return value of "java.util.Map.get(Object)" is null
        at __randomizedtesting.SeedInfo.seed([E53385B3A635A5D7:40DCA336772BE350]:0)
        at org.elasticsearch.search.aggregations.bucket.RandomSamplerIT.testRandomSamplerHistogram(RandomSamplerIT.java:158)
  1> [2022-06-28T13:42:44,203][INFO ][o.e.s.a.b.RandomSamplerIT] [suite] [RandomSamplerIT]: cleaning up after suite
  1> [2022-06-28T13:42:44,245][INFO ][o.e.c.m.MetadataDeleteIndexService] [node_s1] [idx/-oAgidWCSni9fABrZ343RA] deleting index
  1> [2022-06-28T13:42:44,259][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,259][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,261][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,261][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,263][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,263][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,265][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,265][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,266][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,266][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,268][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,268][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,270][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,270][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,272][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,272][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,274][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,274][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,275][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,275][WARN ][o.e.d.c.s.Settings       ] [node_s0] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,278][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,278][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,280][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,281][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,283][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,283][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,285][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,285][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,287][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,287][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,289][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,289][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,291][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,291][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,292][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,293][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,294][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,294][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,295][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,295][WARN ][o.e.d.c.s.Settings       ] [node_s1] data_stream.dataset="deprecation.elasticsearch" data_stream.namespace="default" data_stream.type="logs" elasticsearch.event.category="settings" event.code="index.data_path" message="[index.data_path] setting was deprecated in Elasticsearch and will be removed in a future release."
  1> [2022-06-28T13:42:44,298][INFO ][o.e.c.m.MetadataIndexTemplateService] [node_s1] removing template [random_index_template]
  1> [2022-06-28T13:42:44,305][INFO ][o.e.n.Node               ] [suite] stopping ...
  1> [2022-06-28T13:42:44,307][INFO ][o.e.c.c.Coordinator      ] [node_s0] master node [{node_s1}{aCxOfFqSS9-f9aSgQLWdQA}{2xk-ap_kRRC5Udjf2tmjfA}{node_s1}{127.0.0.1}{127.0.0.1:14802}{cdfhilmrstw}] disconnected, restarting discovery
  1> [2022-06-28T13:42:44,309][INFO ][o.e.t.ClusterConnectionManager] [node_s1] transport connection to [{node_s0}{j1FKeyVmStGiR1Ms_cPlqg}{lOpr3tiZTs2jfDh32aWNgg}{node_s0}{127.0.0.1}{127.0.0.1:14801}{cdfhilmrstw}] closed by remote
  1> [2022-06-28T13:42:44,311][INFO ][o.e.n.Node               ] [suite] stopped
  1> [2022-06-28T13:42:44,311][INFO ][o.e.n.Node               ] [suite] closing ...
  1> [2022-06-28T13:42:44,311][INFO ][o.e.c.s.MasterService    ] [node_s1] node-left[{node_s0}{j1FKeyVmStGiR1Ms_cPlqg}{lOpr3tiZTs2jfDh32aWNgg}{node_s0}{127.0.0.1}{127.0.0.1:14801}{cdfhilmrstw} reason: disconnected], term: 1, version: 24, delta: removed {{node_s0}{j1FKeyVmStGiR1Ms_cPlqg}{lOpr3tiZTs2jfDh32aWNgg}{node_s0}{127.0.0.1}{127.0.0.1:14801}{cdfhilmrstw}}
  1> [2022-06-28T13:42:44,314][INFO ][o.e.n.Node               ] [suite] closed
  1> [2022-06-28T13:42:44,315][INFO ][o.e.n.Node               ] [suite] stopping ...
  1> [2022-06-28T13:42:44,316][INFO ][o.e.c.s.ClusterApplierService] [node_s1] removed {{node_s0}{j1FKeyVmStGiR1Ms_cPlqg}{lOpr3tiZTs2jfDh32aWNgg}{node_s0}{127.0.0.1}{127.0.0.1:14801}{cdfhilmrstw}}, term: 1, version: 24, reason: Publication{term=1, version=24}
  1> [2022-06-28T13:42:44,320][INFO ][o.e.n.Node               ] [suite] stopped
  1> [2022-06-28T13:42:44,320][INFO ][o.e.n.Node               ] [suite] closing ...
  1> [2022-06-28T13:42:44,321][INFO ][o.e.n.Node               ] [suite] closed
  2> NOTE: leaving temporary files on disk at: /home/brownbear/src/elasticsearch/server/build/testrun/internalClusterTest/temp/org.elasticsearch.search.aggregations.bucket.RandomSamplerIT_E53385B3A635A5D7-002
  2> NOTE: test params are: codec=Asserting(Lucene92): {index_uuid=PostingsFormat(name=Asserting), kind=Lucene90, _id=Lucene90, type=Lucene90, kind.keyword=Lucene90}, docValues:{_seq_no=DocValuesFormat(name=Lucene90), number=DocValuesFormat(name=Asserting), monotonic=DocValuesFormat(name=Lucene90), _primary_term=DocValuesFormat(name=Asserting), kind.keyword=DocValuesFormat(name=Lucene90), _version=DocValuesFormat(name=Asserting)}, maxPointsInLeafNode=213, maxMBSortInHeap=6.6676296283317695, sim=Asserting(RandomSimilarity(queryNorm=true): {}), locale=nn-NO, timezone=Asia/Rangoon
  2> NOTE: Linux 5.15.0-40-generic amd64/Private Build 18-ea (64-bit)/cpus=48,threads=1,free=367166168,total=536870912
  2> NOTE: All tests run in this JVM: [RandomSamplerIT]

Tests with failures:
 - org.elasticsearch.search.aggregations.bucket.RandomSamplerIT.testRandomSamplerHistogram

```
server/src/internalClusterTest/java/org/elasticsearch/search/aggregations/bucket/RandomSamplerIT.java
sampledDocCount.compute(bucket.getKeyAsString(), (k, v) -> bucket.getDocCount() + (v == null ? 0 : v));
            }
        }
        for (String key : sampledDocCount.keySet()) {
            sampledDocCount.put(key, sampledDocCount.get(key) / NUM_SAMPLE_RUNS);
            sampleRandomValue.put(key, sampleRandomValue.get(key) / NUM_SAMPLE_RUNS);
            sampleMonotonicValue.put(key, sampleMonotonicValue.get(key) / NUM_SAMPLE_RUNS);
        }
        SearchResponse trueValueResponse = client().prepareSearch("idx")
            .addAggregation(
                histogram("histo").field(NUMERIC_VALUE)
                    .interval(5.0)
                    .subAggregation(avg("mean_monotonic").field(MONOTONIC_VALUE))
                    .subAggregation(avg("mean_numeric").field(NUMERIC_VALUE))
            )
            .get();
        Histogram histogram = trueValueResponse.getAggregations().get("histo");
        for (Histogram.Bucket bucket : histogram.getBuckets()) {
            long numDocs = bucket.getDocCount();
            double errorRate = Math.pow(1.0 / (0.5 * numDocs), 0.35);
            double countError = errorRate * numDocs;
            assertThat(Math.abs(sampledDocCount.get(bucket.getKeyAsString()) - numDocs), lessThan(countError));
            double trueMonotonic = ((Avg) bucket.getAggregations().get("mean_monotonic")).getValue();
            double trueRandom = ((Avg) bucket.getAggregations().get("mean_numeric")).getValue();
            assertThat(Math.abs(sampleMonotonicValue.get(bucket.getKeyAsString()) - trueMonotonic), lessThan(trueMonotonic * errorRate));
            assertThat(Math.abs(sampleRandomValue.get(bucket.getKeyAsString()) - trueRandom), lessThan(trueRandom * errorRate));
        }
    }
}