[CI] SemanticInferenceMetadataFieldsRecoveryTests testSnapshotRecovery {p0=false p1=true} failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic-platform-support #9468 / almalinux-8_platform-support-unix
• elasticsearch-periodic-platform-support #9398 / ubuntu-2404-aarch64_checkpart2_platform-support-arm

Reproduction Line:

./gradlew ":x-pack:plugin:inference:test" --tests "org.elasticsearch.xpack.inference.mapper.SemanticInferenceMetadataFieldsRecoveryTests.testSnapshotRecovery {p0=false p1=false}" -Dtests.seed=B878CA3A936CD463 -Dtests.locale=eo-Latn-001 -Dtests.timezone=Poland -Druntime.java=24

Applicable branches:
8.18

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

org.elasticsearch.index.mapper.DocumentParsingException: [1:991] failed to parse field [_inference_fields] of type [_inference_fields] in document with id '1'. Preview of field's value: 'null'

Issue Reasons:

• [8.18] 2 failures in test testSnapshotRecovery {p0=false p1=true} (0.5% fail rate in 366 executions)
• [8.18] 2 failures in pipeline elasticsearch-periodic-platform-support (18.2% fail rate in 11 executions)

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

[elasticsearchmachine]

Pinging @elastic/search-eng (Team:SearchOrg)

[elasticsearchmachine]

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

[jimczi]

Fixed by #132420