[CI] LongFieldMapperTests testSyntheticSourceInNestedObject failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic-platform-support #10200 / windows-2025_checkpart1_platform-support-windows
• elasticsearch-pull-request #87311 / part-1
• elasticsearch-pull-request #87307 / part-1
• elasticsearch-pull-request #87219 / part-1

Reproduction Line:

gradlew ":server:test" --tests "org.elasticsearch.index.mapper.LongFieldMapperTests.testSyntheticSourceInNestedObject" -Dtests.seed=B6E99B6B9DF3B40E -Dtests.locale=nb-Latn-NO -Dtests.timezone=Antarctica/Troll -Druntime.java=24

Applicable branches:
main

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: 
Expected: "{\"obj\":{\"field\":-6847498379602012160}}"
     but: was "{\"obj\":{\"field\":-6847498379602012000}}"

Issue Reasons:

• [main] 4 failures in test testSyntheticSourceInNestedObject (1.0% fail rate in 400 executions)
• [main] 3 failures in step part-1 (1.5% fail rate in 206 executions)
• [main] 3 failures in pipeline elasticsearch-pull-request (1.5% fail rate in 201 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] 4 failures in test testSyntheticSourceInNestedObject (1.0% fail rate in 400 executions)
• [main] 3 failures in step part-1 (1.5% fail rate in 206 executions)
• [main] 3 failures in pipeline elasticsearch-pull-request (1.5% fail rate in 201 executions)

Build Scans:

• elasticsearch-periodic-platform-support #10200 / windows-2025_checkpart1_platform-support-windows
• elasticsearch-pull-request #87311 / part-1
• elasticsearch-pull-request #87307 / part-1
• elasticsearch-pull-request #87219 / part-1

[elasticsearchmachine]

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

[ivancea]

@smalyshev Assigning this to you, as I think you're working on it with this PR: #133423