**Build scan:**
https://gradle-enterprise.elastic.co/s/lq3iggq2c5w7y/tests/:server:test/org.elasticsearch.search.builder.SearchSourceBuilderTests/testFromXContent

**Reproduction line:**
```
gradlew ':server:test' --tests "org.elasticsearch.search.builder.SearchSourceBuilderTests.testFromXContent" -Dtests.seed=418ECB21FC1452B8 -Dtests.locale=vi -Dtests.timezone=Brazil/DeNoronha -Druntime.java=20
```

**Applicable branches:**
main

**Reproduces locally?:**
Yes

**Failure history:**
https://gradle-enterprise.elastic.co/scans/tests?tests.container=org.elasticsearch.search.builder.SearchSourceBuilderTests&tests.test=testFromXContent

**Failure excerpt:**
```
org.elasticsearch.xcontent.XContentParseException: [5:5] malformed query within the [sub_searches] field; found START_ARRAY

  at __randomizedtesting.SeedInfo.seed([418ECB21FC1452B8:60E6FE3975B3B262]:0)
  at org.elasticsearch.search.builder.SearchSourceBuilder.parseXContent(SearchSourceBuilder.java:1568)
  at org.elasticsearch.search.builder.SearchSourceBuilder.parseXContent(SearchSourceBuilder.java:1258)
  at org.elasticsearch.search.builder.SearchSourceBuilderTests.assertParseSearchSource(SearchSourceBuilderTests.java:104)
  at org.elasticsearch.search.builder.SearchSourceBuilderTests.testFromXContent(SearchSourceBuilderTests.java:80)
  at jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
  at java.lang.reflect.Method.invoke(Method.java:578)
  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:1623)

```
server/src/main/java/org/elasticsearch/search/builder/SearchSourceBuilder.java
out.writeList(scriptFields);
        }
        out.writeVInt(size);
        boolean hasSorts = sorts != null;
        out.writeBoolean(hasSorts);
        if (hasSorts) {
            out.writeNamedWriteableList(sorts);
        }
        boolean hasStats = stats != null;
        out.writeBoolean(hasStats);
        if (hasStats) {
            out.writeStringCollection(stats);
        }
        out.writeOptionalWriteable(suggestBuilder);
        out.writeVInt(terminateAfter);
        out.writeOptionalTimeValue(timeout);
        out.writeBoolean(trackScores);
        out.writeOptionalBoolean(version);
        out.writeOptionalBoolean(seqNoAndPrimaryTerm);
        out.writeNamedWriteableList(extBuilders);
        out.writeBoolean(profile);
        out.writeOptionalWriteable(searchAfterBuilder);
        out.writeOptionalWriteable(sliceBuilder);
        out.writeOptionalWriteable(collapse);
        out.writeOptionalInt(trackTotalHitsUpTo);
        if (out.getTransportVersion().onOrAfter(TransportVersion.V_7_10_0)) {
            out.writeBoolean(fetchFields != null);
            if (fetchFields != null) {
                out.writeList(fetchFields);
            }