This is a new test case which has failed a few times now since being added.

Build scan:
https://gradle-enterprise.elastic.co/s/nckptifuyp4v2/tests/:x-pack:plugin:ilm:qa:multi-node:javaRestTest/org.elasticsearch.xpack.ilm.actions.RollupActionIT/testRollupIndexAndSetNewRollupPolicy#1

Repro line:
./gradlew ':x-pack:plugin:ilm:qa:multi-node:javaRestTest' --tests "org.elasticsearch.xpack.ilm.actions.RollupActionIT.testRollupIndexAndSetNewRollupPolicy" -Dtests.seed=F0A4BF22F8036B7E -Dtests.security.manager=true -Dtests.locale=sk-SK -Dtests.timezone=Pacific/Truk -Druntime.java=11

Reproduces locally?:
Nope.

Applicable branches:
master and 7.x (error on the 7.x build looked a bit different though)

Failure history:
https://gradle-enterprise.elastic.co/scans/tests?search.relativeStartTime=P7D&search.timeZoneId=America/Los_Angeles&tests.container=org.elasticsearch.xpack.ilm.actions.RollupActionIT&tests.sortField=FAILED&tests.unstableOnly=true

Failure excerpt:

org.elasticsearch.xpack.ilm.actions.RollupActionIT > testRollupIndexAndSetNewRollupPolicy FAILED
    java.lang.AssertionError
        at __randomizedtesting.SeedInfo.seed([F0A4BF22F8036B7E:7FF7996A3D79E9A]:0)