[CI] SearchTemplateRequestTests testConcurrentEquals failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic #5762 / release-tests
• elasticsearch-pull-request #49522 / release-tests
• elasticsearch-periodic #5757 / release-tests

Reproduction Line:

./gradlew ":modules:lang-mustache:test" --tests "org.elasticsearch.script.mustache.SearchTemplateRequestTests.testConcurrentSerialization" -Dtests.seed=2A2139F411B3F660 -Dbuild.snapshot=false -Dtests.jvm.argline="-Dbuild.snapshot=false" -Dlicense.key=x-pack/license-tools/src/test/resources/public.key -Dtests.locale=ff-Adlm-GN -Dtests.timezone=Pacific/Niue -Druntime.java=23

Applicable branches:
main

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: 
Expected: <org.elasticsearch.script.mustache.SearchTemplateRequest/unset>
     but: was <org.elasticsearch.script.mustache.SearchTemplateRequest/unset>

Issue Reasons:

• [main] 3 consecutive failures in step release-tests
• [main] 3 failures in test testConcurrentEquals (1.2% fail rate in 257 executions)
• [main] 3 failures in step release-tests (37.5% fail rate in 8 executions)
• [main] 2 failures in pipeline elasticsearch-periodic (50.0% fail rate in 4 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] 3 consecutive failures in step release-tests
• [main] 3 failures in test testConcurrentEquals (1.2% fail rate in 257 executions)
• [main] 3 failures in step release-tests (37.5% fail rate in 8 executions)
• [main] 2 failures in pipeline elasticsearch-periodic (50.0% fail rate in 4 executions)

Build Scans:

• elasticsearch-periodic #5762 / release-tests
• elasticsearch-pull-request #49522 / release-tests
• elasticsearch-periodic #5757 / release-tests

[elasticsearchmachine]

Pinging @elastic/es-core-infra (Team:Core/Infra)

[ldematte]

This (and related tests) are consistently failing because SearchTemplateRequest#SearchRequest#indicesOptions.gatekeeperOptions() is different (allowSelectors).
Will try and find where it started failing.

[ldematte]

After some git bisecting, it seems this started failing with #118614 (c3839e1), so I'm moving this (and all other related failures) over to data management.

[elasticsearchmachine]

Pinging @elastic/es-data-management (Team:Data Management)