[CI] EsqlSpecIT test {lookup-join.MvJoinKeyFromRow ASYNC} failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic-platform-support #9157 / windows-2025_checkpart3_platform-support-windows
• elasticsearch-pull-request #78391 / part-3

Reproduction Line:

gradlew ":x-pack:plugin:esql:qa:server:single-node:javaRestTest" --tests "org.elasticsearch.xpack.esql.qa.single_node.EsqlSpecIT" -Dtests.method="test {lookup-join.MvJoinKeyFromRow ASYNC}" -Dtests.seed=F1A334C9DE643CB -Dtests.locale=af-ZA -Dtests.timezone=ECT -Druntime.java=24

Applicable branches:
main

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: Expected a list containing
0: expected "Line 2:3: evaluation of [LOOKUP JOIN languages_lookup_non_unique_key ON language_code] failed, treating result as null. Only first 20 failures recorded." but was <missing>
1: expected "Line 2:3: java.lang.IllegalArgumentException: LOOKUP JOIN encountered multi-value" but was <missing>

Issue Reasons:

• [main] 2 failures in test test {lookup-join.MvJoinKeyFromRow ASYNC} (0.3% fail rate in 690 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 test {lookup-join.MvJoinKeyFromRow ASYNC} (0.3% fail rate in 690 executions)

Build Scans:

• elasticsearch-periodic-platform-support #9157 / windows-2025_checkpart3_platform-support-windows
• elasticsearch-pull-request #78391 / part-3

[elasticsearchmachine]

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