[CI] FullClusterRestartSystemIndexCompatibilityIT testAsyncSearchIndexMigration {p0=9.0.3} failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic-platform-support #8705 / windows-2022_checkpart1_platform-support-windows
• elasticsearch-periodic-platform-support #8585 / windows-2025_checkpart1_platform-support-windows

Reproduction Line:

gradlew ":qa:lucene-index-compatibility:javaRestTest" --tests "org.elasticsearch.lucene.FullClusterRestartSystemIndexCompatibilityIT" -Dtests.method="testAsyncSearchIndexMigration {p0=8.18.0}" -Dtests.seed=B111B3EA704A21BB -Dtests.locale=ro-Latn-RO -Dtests.timezone=EST5EDT -Druntime.java=24

Applicable branches:
9.0

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: expected:<2431> but was:<0>

Issue Reasons:

• [9.0] 2 failures in test testAsyncSearchIndexMigration {p0=9.0.3} (0.4% fail rate in 554 executions)
• [9.0] 2 failures in pipeline elasticsearch-periodic-platform-support (9.5% fail rate in 21 executions)

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

[elasticsearchmachine]

Pinging @elastic/es-search-foundations (Team:Search Foundations)