Build Scans:

• elasticsearch-intake #26642 / 9.1.2_bwc-snapshots
• elasticsearch-pull-request #84849 / 9.1.2_part_3_bwc-snapshots
• elasticsearch-pull-request #84849 / 9.0.5_part_3_bwc-snapshots
• elasticsearch-pull-request #84849 / 8.19.2_part_3_bwc-snapshots
• elasticsearch-pull-request #84849 / pr-upgrade-part-3
• elasticsearch-pull-request #84724 / 8.19.1_part_3_bwc-snapshots
• elasticsearch-pull-request #84703 / 9.0.5_part_3_bwc-snapshots
• elasticsearch-pull-request #84703 / 9.1.1_part_3_bwc-snapshots
• elasticsearch-pull-request #84688 / 9.0.5_part_3_bwc-snapshots
• elasticsearch-pull-request #84688 / 8.19.1_part_3_bwc-snapshots

Reproduction Line:

./gradlew ":x-pack:plugin:esql:qa:server:mixed-cluster:v9.1.2#javaRestTest" -Dtests.class="org.elasticsearch.xpack.esql.qa.mixed.MixedClusterEsqlSpecIT" -Dtests.method="test {csv-spec:lookup-join.MvJoinKeyFromRowExpanded}" -Dtests.seed=E93F6B86F0402D47 -Dtests.bwc=true -Dtests.locale=et -Dtests.timezone=Asia/Chongqing -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 3:3: 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 3:3: java.lang.IllegalArgumentException: LOOKUP JOIN encountered multi-value" but was <missing> 

Issue Reasons:

• [main] 4 consecutive failures in step 9.0.5_part_3_bwc-snapshots
• [main] 3 consecutive failures in step 8.19.1_part_3_bwc-snapshots
• [main] 16 failures in test test {csv-spec:lookup-join.MvJoinKeyFromRowExpanded} (4.6% fail rate in 346 executions)
• [main] 4 failures in step pr-upgrade-part-3 (3.1% fail rate in 131 executions)
• [main] 4 failures in step 9.0.5_part_3_bwc-snapshots (100.0% fail rate in 4 executions)
• [main] 2 failures in step 9.1.1_part_3_bwc-snapshots (2.7% fail rate in 73 executions)
• [main] 3 failures in step 8.19.1_part_3_bwc-snapshots (100.0% fail rate in 3 executions)
• [main] 7 failures in pipeline elasticsearch-pull-request (4.8% fail rate in 145 executions)

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