[CI] ExchangeServiceTests testExchangeSourceContinueOnFailure failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-intake #17898 / part3
• elasticsearch-intake #17401 / part3

Reproduction Line:

./gradlew ":x-pack:plugin:esql:compute:test" --tests "org.elasticsearch.compute.operator.exchange.ExchangeServiceTests.testExchangeSourceContinueOnFailure" -Dtests.seed=23414301FFD8431B -Dtests.locale=fr-MA -Dtests.timezone=Zulu -Druntime.java=23

Applicable branches:
9.0

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: 
Expected: <7>
     but: was <6>

Issue Reasons:

• [9.0] 2 failures in test testExchangeSourceContinueOnFailure (0.3% fail rate in 646 executions)
• [9.0] 2 failures in step part3 (2.5% fail rate in 79 executions)
• [9.0] 2 failures in pipeline elasticsearch-intake (2.5% fail rate in 79 executions)

Note:
This issue was created using new test triage automation. Please report issues or feedback to es-delivery.

[elasticsearchmachine]

This has been muted on branch 9.0

Mute Reasons:

• [9.0] 2 failures in test testExchangeSourceContinueOnFailure (0.3% fail rate in 646 executions)
• [9.0] 2 failures in step part3 (2.5% fail rate in 79 executions)
• [9.0] 2 failures in pipeline elasticsearch-intake (2.5% fail rate in 79 executions)

Build Scans:

• elasticsearch-intake #17898 / part3
• elasticsearch-intake #17401 / part3

[elasticsearchmachine]

Pinging @elastic/es-analytical-engine (Team:Analytics)

[idegtiarenko]

Interesting, this should be fixed by #121603 that was backported to 9 last week.

[dnhatn]

@idegtiarenko Thanks for taking a look. The fix in #21603 wasn't good enough. I've opened #122446.