[CI] AdaptiveAllocationsScalerTests testAutoscaling_scaleDownToZeroAllocations failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic #4206 / release-tests
• elasticsearch-periodic #4202 / release-tests

Reproduction Line:

./gradlew ":x-pack:plugin:ml:test" --tests "org.elasticsearch.xpack.ml.inference.adaptiveallocations.AdaptiveAllocationsScalerTests.testAutoscaling_scaleDownToZeroAllocations" -Dtests.seed=39DDA1B60BDA11D5 -Dbuild.snapshot=false -Dtests.jvm.argline="-Dbuild.snapshot=false" -Dlicense.key=x-pack/license-tools/src/test/resources/public.key -Dtests.locale=pa-Arab -Dtests.timezone=Asia/Riyadh -Druntime.java=22

Applicable branches:
main

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: 
Expected: <0>
     but: was null

Issue Reasons:

• [main] 2 consecutive failures in step release-tests
• [main] 2 failures in test testAutoscaling_scaleDownToZeroAllocations (1.8% fail rate in 112 executions)
• [main] 2 failures in step release-tests (100.0% fail rate in 2 executions)
• [main] 2 failures in pipeline elasticsearch-periodic (100.0% fail rate in 2 executions)

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

[elasticsearchmachine]

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

[jan-elastic]

#113665