[CI] IndexStatsIT testFilterCacheStats failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-intake #28173 / part1
• elasticsearch-periodic-platform-support #10486 / ubuntu-2404_platform-support-unix
• elasticsearch-periodic #10459 / openjdk21_checkpart1_java-fips-matrix

Reproduction Line:

./gradlew ":server:internalClusterTest" --tests "org.elasticsearch.indices.stats.IndexStatsIT.testFilterCacheStats" -Dtests.seed=BF84DD8726022190 -Dtests.locale=en-GH -Dtests.timezone=Europe/Sofia -Druntime.java=24

Applicable branches:
9.1

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: Routing entry for shard [index][3], node[j3r1PTF8RrisUVBzIU7F-Q], [P], s[STARTED], a[id=RIV28-JxQi22IUtwF1WxKw], failed_attempts[0]
Expected: <1L>
     but: was <0L>

Issue Reasons:

• [9.1] 3 failures in test testFilterCacheStats (0.8% fail rate in 356 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] 2 failures in test testFilterCacheStats (0.4% fail rate in 506 executions)

Build Scans:

• elasticsearch-periodic #6887 / openjdk21_checkpart1_java-fips-matrix
• elasticsearch-pull-request #60929 / part-1

[elasticsearchmachine]

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

[elasticsearchmachine]

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