[CI] CrossClusterAsyncEnrichStopIT testEnrichAfterStop failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic-platform-support #9462 / debian-12_platform-support-unix
• elasticsearch-periodic-platform-support #9434 / amazonlinux-2_platform-support-aws

Reproduction Line:

./gradlew ":x-pack:plugin:esql:internalClusterTest" --tests "org.elasticsearch.xpack.esql.action.CrossClusterAsyncEnrichStopIT.testEnrichAfterStop" -Dtests.seed=AB5262D6307DCCD8 -Dtests.locale=bm -Dtests.timezone=Africa/Bangui -Druntime.java=24

Applicable branches:
8.19

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.util.ConcurrentModificationException: null

Issue Reasons:

• [8.19] 2 failures in test testEnrichAfterStop (1.4% fail rate in 147 executions)
• [8.19] 2 failures in pipeline elasticsearch-periodic-platform-support (40.0% fail rate in 5 executions)

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

[elasticsearchmachine]

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