It does not reproduce locally. I found this error in the logs which looks like a possible cause.
```
[2022-07-30T01:22:31,499][ERROR][o.e.r.s.FileSettingsService] [[elasticsearch[file-settings-watcher]]] Error processing operator settings json file
  1> java.lang.IllegalStateException: Error processing state change request for file_settings, errors: org.elasticsearch.xcontent.XContentParseException: [1:0] [reserved_state_chunk] Expected START_OBJECT but was: null
  1> 	at org.elasticsearch.xcontent.ObjectParser.throwExpectedStartObject(ObjectParser.java:330)
  1> 	at org.elasticsearch.xcontent.ObjectParser.parse(ObjectParser.java:275)
  1> 	at org.elasticsearch.xcontent.ConstructingObjectParser.parse(ConstructingObjectParser.java:166)
  1> 	at org.elasticsearch.xcontent.ConstructingObjectParser.apply(ConstructingObjectParser.java:158)
  1> 	at org.elasticsearch.reservedstate.service.ReservedClusterStateService.process(ReservedClusterStateService.java:103)
  1> 	at org.elasticsearch.reservedstate.service.FileSettingsService.processFileSettings(FileSettingsService.java:308)
  1> 	at org.elasticsearch.reservedstate.service.FileSettingsService.lambda$startWatcher$3(FileSettingsService.java:245)
  1> 	at java.base/java.lang.Thread.run(Thread.java:833)

  1> 	at org.elasticsearch.reservedstate.service.ReservedClusterStateService.process(ReservedClusterStateService.java:109) ~[main/:?]
  1> 	at org.elasticsearch.reservedstate.service.FileSettingsService.processFileSettings(FileSettingsService.java:308) ~[main/:?]
  1> 	at org.elasticsearch.reservedstate.service.FileSettingsService.lambda$startWatcher$3(FileSettingsService.java:245) ~[main/:?]
  1> 	at java.lang.Thread.run(Thread.java:833) ~[?:?]
  1> Caused by: org.elasticsearch.xcontent.XContentParseException: [1:0] [reserved_state_chunk] Expected START_OBJECT but was: null
  1> 	at org.elasticsearch.xcontent.ObjectParser.throwExpectedStartObject(ObjectParser.java:330) ~[elasticsearch-x-content-8.5.0-SNAPSHOT.jar:8.5.0-SNAPSHOT]
  1> 	at org.elasticsearch.xcontent.ObjectParser.parse(ObjectParser.java:275) ~[elasticsearch-x-content-8.5.0-SNAPSHOT.jar:8.5.0-SNAPSHOT]
  1> 	at org.elasticsearch.xcontent.ConstructingObjectParser.parse(ConstructingObjectParser.java:166) ~[elasticsearch-x-content-8.5.0-SNAPSHOT.jar:8.5.0-SNAPSHOT]
  1> 	at org.elasticsearch.xcontent.ConstructingObjectParser.apply(ConstructingObjectParser.java:158) ~[elasticsearch-x-content-8.5.0-SNAPSHOT.jar:8.5.0-SNAPSHOT]
  1> 	at org.elasticsearch.reservedstate.service.ReservedClusterStateService.process(ReservedClusterStateService.java:103) ~[main/:?]
  1> 	... 3 more
  1> [2022-07-30T01:22:31,502][INFO ][o.e.r.s.FileSettingsService] [[elasticsearch[file-settings-watcher]]] processing path [/mnt/secret/elastic+elasticsearch+main+periodic+ear/server/build/testrun/internalClusterTest/temp/org.elasticsearch.reservedstate.service.FileSettingsServiceIT_129CA1A8D872CBA3-001/tempDir-003/config/operator/settings.json] for [file_settings]
```


**Build scan:**
https://gradle-enterprise.elastic.co/s/pijicvldxziw4/tests/:server:internalClusterTest/org.elasticsearch.reservedstate.service.FileSettingsServiceIT/testSettingsApplied

**Reproduction line:**
`./gradlew ':server:internalClusterTest' --tests "org.elasticsearch.reservedstate.service.FileSettingsServiceIT.testSettingsApplied" -Dtests.seed=129CA1A8D872CBA3 -Dtests.locale=sr-BA -Dtests.timezone=Asia/Kamchatka -Druntime.java=17`

**Applicable branches:**
main

**Reproduces locally?:**
No

**Failure history:**
https://gradle-enterprise.elastic.co/scans/tests?tests.container=org.elasticsearch.reservedstate.service.FileSettingsServiceIT&tests.test=testSettingsApplied

**Failure excerpt:**
```
java.lang.Exception: Test abandoned because suite timeout was reached.

  at __randomizedtesting.SeedInfo.seed([129CA1A8D872CBA3]:0)

```
server/src/internalClusterTest/java/org/elasticsearch/reservedstate/service/FileSettingsServiceIT.java
/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the Elastic License
 * 2.0 and the Server Side Public License, v 1; you may not use this file except
 * in compliance with, at your election, the Elastic License 2.0 or the Server
 * Side Public License, v 1.
 */
package org.elasticsearch.reservedstate.service;
import org.elasticsearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
import org.elasticsearch.action.admin.cluster.state.ClusterStateRequest;
import org.elasticsearch.action.admin.cluster.state.ClusterStateResponse;
import org.elasticsearch.client.internal.Client;
import org.elasticsearch.cluster.ClusterChangedEvent;
import org.elasticsearch.cluster.ClusterStateListener;
import org.elasticsearch.cluster.metadata.ReservedStateErrorMetadata;
import org.elasticsearch.cluster.metadata.ReservedStateHandlerMetadata;
import org.elasticsearch.cluster.metadata.ReservedStateMetadata;
import org.elasticsearch.cluster.service.ClusterService;