[CI] IndexStatsIT testConcurrentIndexingAndStatsRequests failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic #7342 / openjdk23_entitlements_true_checkpart1_java-matrix
• elasticsearch-periodic-platform-support #7364 / rhel-9_platform-support-unix

Reproduction Line:

./gradlew ":server:internalClusterTest" --tests "org.elasticsearch.indices.stats.IndexStatsIT.testThrottleStats" -Dtests.seed=89A7CF4ED59E5D2 -Dtests.jvm.argline="-Des.entitlements.enabled=true" -Dtests.locale=ks-Arab -Dtests.timezone=Pacific/Honolulu -Druntime.java=23

Applicable branches:
main

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: Shard [test][0] is still locked after 5 sec waiting

Issue Reasons:

• [main] 2 failures in test testConcurrentIndexingAndStatsRequests (2.0% fail rate in 102 executions)

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

[elasticsearchmachine]

Pinging @elastic/es-search (Team:Search)

[elasticsearchmachine]

Pinging @elastic/es-distributed-indexing (Team:Distributed Indexing)