[CI] HierarchicalKMeansTests testHKmeans failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-intake #25023 / part1
• elasticsearch-periodic-platform-support #9122 / rhel-8_platform-support-unix
• elasticsearch-intake #24859 / part1

Reproduction Line:

./gradlew ":server:test" --tests "org.elasticsearch.index.codec.vectors.cluster.HierarchicalKMeansTests.testHKmeans" -Dtests.seed=347BBF52C5C219D5 -Dtests.locale=fy -Dtests.timezone=Japan -Druntime.java=24

Applicable branches:
main

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.ArrayIndexOutOfBoundsException: Index -1 out of bounds for length 8

Issue Reasons:

• [main] 3 failures in test testHKmeans (1.1% fail rate in 278 executions)
• [main] 2 failures in step part1 (6.5% fail rate in 31 executions)
• [main] 2 failures in pipeline elasticsearch-intake (6.5% fail rate in 31 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 testHKmeans (0.9% fail rate in 232 executions)

Build Scans:

• elasticsearch-periodic-platform-support #9122 / rhel-8_platform-support-unix
• elasticsearch-intake #24859 / part1

[elasticsearchmachine]

Pinging @elastic/es-search-relevance (Team:Search Relevance)