[CI] ThreadPoolMergeExecutorServiceTests testIORateIsAdjustedForRunningMergeTasks failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic #7286 / openjdk24_entitlements_false_checkpart1_java-matrix
• elasticsearch-pull-request #64612 / part-1

Reproduction Line:

./gradlew ":server:test" --tests "org.elasticsearch.index.engine.ThreadPoolMergeExecutorServiceTests.testIORateIsAdjustedForRunningMergeTasks" -Dtests.seed=9BD0AF493A33E7D -Dtests.jvm.argline="-Des.entitlements.enabled=false" -Dtests.locale=zh-Latn -Dtests.timezone=America/Lima -Druntime.java=24

Applicable branches:
main

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: 
Expected: is <15288239L>
     but: was <18874368L>

Issue Reasons:

• [main] 2 failures in test testIORateIsAdjustedForRunningMergeTasks (0.3% fail rate in 666 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 main

Mute Reasons:

• [main] 2 failures in test testIORateIsAdjustedForRunningMergeTasks (0.3% fail rate in 666 executions)

Build Scans:

• elasticsearch-periodic #7286 / openjdk24_entitlements_false_checkpart1_java-matrix
• elasticsearch-pull-request #64612 / part-1

[elasticsearchmachine]

Pinging @elastic/es-distributed-indexing (Team:Distributed Indexing)