[CI] ClassificationIT testWithOnlyTrainingRowsAndTrainingPercentIsFifty_DependentVariableIsInteger failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic #6276 / openjdk17_checkpart4_java-fips-matrix
• elasticsearch-periodic #6178 / openjdk17_checkpart4_java-matrix

Reproduction Line:

./gradlew ":x-pack:plugin:ml:qa:native-multi-node-tests:javaRestTest" --tests "org.elasticsearch.xpack.ml.integration.ClassificationIT.testWithOnlyTrainingRowsAndTrainingPercentIsFifty_DependentVariableIsInteger" -Dtests.seed=E346077ED9E27ECD -Dtests.locale=et-Latn-EE -Dtests.timezone=Pacific/Fakaofo -Druntime.java=17 -Dtests.fips.enabled=true

Applicable branches:
8.17

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: Stats were: {"id":"classification_training_percent_is_50_integer","state":"started","progress":[{"phase":"reindexing","progress_percent":100},{"phase":"loading_data","progress_percent":100},{"phase":"feature_selection","progress_percent":100},{"phase":"coarse_parameter_search","progress_percent":89},{"phase":"fine_tuning_parameters","progress_percent":0},{"phase":"final_training","progress_percent":0},{"phase":"writing_results","progress_percent":0},{"phase":"inference","progress_percent":0}],"data_counts":{"training_docs_count":150,"test_docs_count":0,"skipped_docs_count":0},"memory_usage":{"timestamp":1739023832439,"peak_usage_bytes":19273,"status":"ok"},"node":{"id":"-J8s7hx6SJm5cQzFb87UNA","name":"javaRestTest-1","ephemeral_id":"-mn9N3rIT9aBHmk7oKT11w","transport_address":"127.0.0.1:45243","attributes":{"ml.config_version":"12.0.0","ml.max_jvm_size":"536870912","ml.allocated_processors":"32","ml.allocated_processors_double":"32.0","ml.machine_memory":"1266
[truncated]

Issue Reasons:

• [8.17] 2 failures in test testWithOnlyTrainingRowsAndTrainingPercentIsFifty_DependentVariableIsInteger (0.4% fail rate in 450 executions)
• [8.17] 2 failures in pipeline elasticsearch-periodic (13.3% fail rate in 15 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 8.x

Mute Reasons:

• [8.x] 2 failures in test testWithOnlyTrainingRowsAndTrainingPercentIsFifty_DependentVariableIsInteger (0.2% fail rate in 826 executions)

Build Scans:

• elasticsearch-intake #17038 / part4
• elasticsearch-periodic #6026 / openjdk22_checkpart4_java-matrix

[elasticsearchmachine]

Pinging @elastic/ml-core (Team:ML)