[CI] TransformIndexerStateTests testStopAtCheckpoint failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic #5608 / openjdk22_java-matrix
• elasticsearch-periodic #5563 / java11_java-fips-matrix

Reproduction Line:

./gradlew ':x-pack:plugin:transform:test' --tests "org.elasticsearch.xpack.transform.transforms.TransformIndexerStateTests.testStopAtCheckpoint" -Dtests.seed=578DB5663E9C3F45 -Dtests.locale=it-IT -Dtests.timezone=Australia/Hobart -Druntime.java=22

Applicable branches:
7.17

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: 
Expected: <5>
     but: was <4>

Issue Reasons:

• [7.17] 2 failures in test testStopAtCheckpoint (0.5% fail rate in 419 executions)
• [7.17] 2 failures in pipeline elasticsearch-periodic (20.0% fail rate in 10 executions)

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

[elasticsearchmachine]

Pinging @elastic/ml-core (Team:ML)