It looks like this failed on the commit which claimed to fix https://github.com/elastic/elasticsearch/issues/100246, so this must be something else.

**Build scan:**
https://gradle-enterprise.elastic.co/s/tnywnp3hpi5r2/tests/:server:test/org.elasticsearch.index.mapper.IdLoaderTests/testSynthesizeIdMultipleSegments
**Reproduction line:**
```
./gradlew ':server:test' --tests "org.elasticsearch.index.mapper.IdLoaderTests.testSynthesizeIdMultipleSegments" -Dtests.seed=7C2B0FEF26582A2D -Dtests.locale=hi -Dtests.timezone=America/Bahia_Banderas -Druntime.java=21
```

**Applicable branches:**
main

**Reproduces locally?:**
Didn't try

**Failure history:**
https://gradle-enterprise.elastic.co/scans/tests?tests.container=org.elasticsearch.index.mapper.IdLoaderTests&tests.test=testSynthesizeIdMultipleSegments
**Failure excerpt:**
```
java.lang.AssertionError: 
Expected: a collection with size <3>
     but: collection size was <6>

  at __randomizedtesting.SeedInfo.seed([7C2B0FEF26582A2D:D24A865EE4A28F57]:0)
  at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:18)
  at org.junit.Assert.assertThat(Assert.java:956)
  at org.junit.Assert.assertThat(Assert.java:923)
  at org.elasticsearch.index.mapper.IdLoaderTests.lambda$testSynthesizeIdMultipleSegments$3(IdLoaderTests.java:111)
  at org.elasticsearch.index.mapper.IdLoaderTests.prepareIndexReader(IdLoaderTests.java:216)
  at org.elasticsearch.index.mapper.IdLoaderTests.testSynthesizeIdMultipleSegments(IdLoaderTests.java:141)
  at jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
  at java.lang.reflect.Method.invoke(Method.java:580)
  at com.carrotsearch.randomizedtesting.RandomizedRunner.invoke(RandomizedRunner.java:1758)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$8.evaluate(RandomizedRunner.java:946)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$9.evaluate(RandomizedRunner.java:982)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$10.evaluate(RandomizedRunner.java:996)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at org.apache.lucene.tests.util.TestRuleSetupTeardownChained$1.evaluate(TestRuleSetupTeardownChained.java:48)
  at org.apache.lucene.tests.util.AbstractBeforeAfterRule$1.evaluate(AbstractBeforeAfterRule.java:43)
  at org.apache.lucene.tests.util.TestRuleThreadAndTestName$1.evaluate(TestRuleThreadAndTestName.java:45)
  at org.apache.lucene.tests.util.TestRuleIgnoreAfterMaxFailures$1.evaluate(TestRuleIgnoreAfterMaxFailures.java:60)
  at org.apache.lucene.tests.util.TestRuleMarkFailure$1.evaluate(TestRuleMarkFailure.java:44)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl$StatementRunner.run(ThreadLeakControl.java:390)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl.forkTimeoutingTask(ThreadLeakControl.java:843)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl$3.evaluate(ThreadLeakControl.java:490)
  at com.carrotsearch.randomizedtesting.RandomizedRunner.runSingleTest(RandomizedRunner.java:955)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$5.evaluate(RandomizedRunner.java:840)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$6.evaluate(RandomizedRunner.java:891)
  at com.carrotsearch.randomizedtesting.RandomizedRunner$7.evaluate(RandomizedRunner.java:902)
  at org.apache.lucene.tests.util.AbstractBeforeAfterRule$1.evaluate(AbstractBeforeAfterRule.java:43)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at org.apache.lucene.tests.util.TestRuleStoreClassName$1.evaluate(TestRuleStoreClassName.java:38)
  at com.carrotsearch.randomizedtesting.rules.NoShadowingOrOverridesOnMethodsRule$1.evaluate(NoShadowingOrOverridesOnMethodsRule.java:40)
  at com.carrotsearch.randomizedtesting.rules.NoShadowingOrOverridesOnMethodsRule$1.evaluate(NoShadowingOrOverridesOnMethodsRule.java:40)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at org.apache.lucene.tests.util.TestRuleAssertionsRequired$1.evaluate(TestRuleAssertionsRequired.java:53)
  at org.apache.lucene.tests.util.AbstractBeforeAfterRule$1.evaluate(AbstractBeforeAfterRule.java:43)
  at org.apache.lucene.tests.util.TestRuleMarkFailure$1.evaluate(TestRuleMarkFailure.java:44)
  at org.apache.lucene.tests.util.TestRuleIgnoreAfterMaxFailures$1.evaluate(TestRuleIgnoreAfterMaxFailures.java:60)
  at org.apache.lucene.tests.util.TestRuleIgnoreTestSuites$1.evaluate(TestRuleIgnoreTestSuites.java:47)
  at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl$StatementRunner.run(ThreadLeakControl.java:390)
  at com.carrotsearch.randomizedtesting.ThreadLeakControl.lambda$forkTimeoutingTask$0(ThreadLeakControl.java:850)
  at java.lang.Thread.run(Thread.java:1583)

```
server/src/test/java/org/elasticsearch/index/mapper/IdLoaderTests.java
var routingBuilder = routing.builder();
        var timeSeriesIdBuilder = new TimeSeriesIdFieldMapper.TimeSeriesIdBuilder(routingBuilder);
        for (Dimension dimension : doc.dimensions) {
            if (dimension.value instanceof Number n) {
                timeSeriesIdBuilder.addLong(dimension.field, n.longValue());
            } else {
                timeSeriesIdBuilder.addString(dimension.field, dimension.value.toString());
            }
        }
        return TsidExtractingIdFieldMapper.createId(
            false,
            routingBuilder,
            timeSeriesIdBuilder.build().toBytesRef(),
            doc.timestamp,
            new byte[16]
        );
    }
    private static IndexRouting.ExtractFromSource createRouting(List<String> routingPaths) {
        var settings = indexSettings(IndexVersion.current(), 2, 1).put(IndexSettings.MODE.getKey(), "time_series")
            .put(IndexSettings.TIME_SERIES_START_TIME.getKey(), "2000-01-01T00:00:00.000Z")
            .put(IndexSettings.TIME_SERIES_END_TIME.getKey(), "2001-01-01T00:00:00.000Z")
            .putList(IndexMetadata.INDEX_ROUTING_PATH.getKey(), routingPaths)
            .build();
        var indexMetadata = IndexMetadata.builder("index").settings(settings).build();
        return (IndexRouting.ExtractFromSource) IndexRouting.fromIndexMetadata(indexMetadata);
    }
    record Doc(long timestamp, List<Dimension> dimensions) {}
    record Dimension(String field, Object value) {}
}