diff --git a/modules/reindex/src/internalClusterTest/java/org/elasticsearch/migration/FeatureMigrationIT.java b/modules/reindex/src/internalClusterTest/java/org/elasticsearch/migration/FeatureMigrationIT.java
index 007359da2fcf0..17847e90cdb05 100644
--- a/modules/reindex/src/internalClusterTest/java/org/elasticsearch/migration/FeatureMigrationIT.java
+++ b/modules/reindex/src/internalClusterTest/java/org/elasticsearch/migration/FeatureMigrationIT.java
@@ -29,6 +29,7 @@
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.indices.AssociatedIndexDescriptor;
 import org.elasticsearch.indices.SystemIndexDescriptor;
 import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.plugins.SystemIndexPlugin;
@@ -90,6 +91,18 @@ public void testMigrateInternalManagedSystemIndex() throws Exception {
         createSystemIndexForDescriptor(EXTERNAL_MANAGED);
         createSystemIndexForDescriptor(EXTERNAL_UNMANAGED);
 
+        CreateIndexRequestBuilder createRequest = prepareCreate(ASSOCIATED_INDEX_NAME);
+        createRequest.setWaitForActiveShards(ActiveShardCount.ALL);
+        createRequest.setSettings(
+            Settings.builder()
+                .put("index.version.created", NEEDS_UPGRADE_VERSION)
+                .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 0)
+                .put("index.hidden", true) // So we don't get a warning
+                .build()
+        );
+        CreateIndexResponse response = createRequest.get();
+        assertTrue(response.isShardsAcknowledged());
+
         ensureGreen();
 
         SetOnce<Boolean> preUpgradeHookCalled = new SetOnce<>();
@@ -226,11 +239,16 @@ public void createSystemIndexForDescriptor(SystemIndexDescriptor descriptor) thr
         CreateIndexRequestBuilder createRequest = prepareCreate(indexName);
         createRequest.setWaitForActiveShards(ActiveShardCount.ALL);
         if (descriptor.getSettings() != null) {
-            createRequest.setSettings(Settings.builder().put("index.version.created", Version.CURRENT).build());
+            createRequest.setSettings(
+                Settings.builder()
+                    .put("index.version.created", Version.CURRENT)
+                    .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 0)
+                    .build()
+            );
         } else {
             createRequest.setSettings(
                 createSimpleSettings(
-                    Version.V_7_0_0,
+                    NEEDS_UPGRADE_VERSION,
                     descriptor.isInternal() ? INTERNAL_UNMANAGED_FLAG_VALUE : EXTERNAL_UNMANAGED_FLAG_VALUE
                 )
             );
@@ -258,6 +276,7 @@ public void createSystemIndexForDescriptor(SystemIndexDescriptor descriptor) thr
     static final String ORIGIN = FeatureMigrationIT.class.getSimpleName();
     static final String FlAG_SETTING_KEY = IndexMetadata.INDEX_PRIORITY_SETTING.getKey();
     static final int INDEX_DOC_COUNT = 100; // arbitrarily chosen
+    public static final Version NEEDS_UPGRADE_VERSION = Version.V_7_0_0;
 
     static final int INTERNAL_MANAGED_FLAG_VALUE = 1;
     static final int INTERNAL_UNMANAGED_FLAG_VALUE = 2;
@@ -268,12 +287,12 @@ public void createSystemIndexForDescriptor(SystemIndexDescriptor descriptor) thr
         .setAliasName(".internal-managed-alias")
         .setPrimaryIndex(".int-man-old")
         .setType(SystemIndexDescriptor.Type.INTERNAL_MANAGED)
-        .setSettings(createSimpleSettings(Version.V_7_0_0, INTERNAL_MANAGED_FLAG_VALUE))
+        .setSettings(createSimpleSettings(NEEDS_UPGRADE_VERSION, INTERNAL_MANAGED_FLAG_VALUE))
         .setMappings(createSimpleMapping(true, true))
         .setOrigin(ORIGIN)
         .setVersionMetaKey(VERSION_META_KEY)
         .setAllowedElasticProductOrigins(Collections.emptyList())
-        .setMinimumNodeVersion(Version.V_7_0_0)
+        .setMinimumNodeVersion(NEEDS_UPGRADE_VERSION)
         .setPriorSystemIndexDescriptors(Collections.emptyList())
         .build();
     static final SystemIndexDescriptor INTERNAL_UNMANAGED = SystemIndexDescriptor.builder()
@@ -282,7 +301,7 @@ public void createSystemIndexForDescriptor(SystemIndexDescriptor descriptor) thr
         .setOrigin(ORIGIN)
         .setVersionMetaKey(VERSION_META_KEY)
         .setAllowedElasticProductOrigins(Collections.emptyList())
-        .setMinimumNodeVersion(Version.V_7_0_0)
+        .setMinimumNodeVersion(NEEDS_UPGRADE_VERSION)
         .setPriorSystemIndexDescriptors(Collections.emptyList())
         .build();
     static final SystemIndexDescriptor EXTERNAL_MANAGED = SystemIndexDescriptor.builder()
@@ -290,12 +309,12 @@ public void createSystemIndexForDescriptor(SystemIndexDescriptor descriptor) thr
         .setAliasName(".external-managed-alias")
         .setPrimaryIndex(".ext-man-old")
         .setType(SystemIndexDescriptor.Type.EXTERNAL_MANAGED)
-        .setSettings(createSimpleSettings(Version.V_7_0_0, EXTERNAL_MANAGED_FLAG_VALUE))
+        .setSettings(createSimpleSettings(NEEDS_UPGRADE_VERSION, EXTERNAL_MANAGED_FLAG_VALUE))
         .setMappings(createSimpleMapping(true, false))
         .setOrigin(ORIGIN)
         .setVersionMetaKey(VERSION_META_KEY)
         .setAllowedElasticProductOrigins(Collections.singletonList(ORIGIN))
-        .setMinimumNodeVersion(Version.V_7_0_0)
+        .setMinimumNodeVersion(NEEDS_UPGRADE_VERSION)
         .setPriorSystemIndexDescriptors(Collections.emptyList())
         .build();
     static final SystemIndexDescriptor EXTERNAL_UNMANAGED = SystemIndexDescriptor.builder()
@@ -304,9 +323,10 @@ public void createSystemIndexForDescriptor(SystemIndexDescriptor descriptor) thr
         .setOrigin(ORIGIN)
         .setVersionMetaKey(VERSION_META_KEY)
         .setAllowedElasticProductOrigins(Collections.singletonList(ORIGIN))
-        .setMinimumNodeVersion(Version.V_7_0_0)
+        .setMinimumNodeVersion(NEEDS_UPGRADE_VERSION)
         .setPriorSystemIndexDescriptors(Collections.emptyList())
         .build();
+    static final String ASSOCIATED_INDEX_NAME = ".my-associated-idx";
 
     static Settings createSimpleSettings(Version creationVersion, int flagSettingValue) {
         return Settings.builder()
@@ -367,6 +387,12 @@ public Collection<SystemIndexDescriptor> getSystemIndexDescriptors(Settings sett
             return Arrays.asList(INTERNAL_MANAGED, INTERNAL_UNMANAGED, EXTERNAL_MANAGED, EXTERNAL_UNMANAGED);
         }
 
+        @Override
+        public Collection<AssociatedIndexDescriptor> getAssociatedIndexDescriptors() {
+
+            return Collections.singletonList(new AssociatedIndexDescriptor(ASSOCIATED_INDEX_NAME, TestPlugin.class.getCanonicalName()));
+        }
+
         @Override
         public void prepareForIndicesMigration(ClusterService clusterService, Client client, ActionListener<Map<String, Object>> listener) {
             listener.onResponse(preMigrationHook.get().apply(clusterService.state()));
diff --git a/server/src/main/java/org/elasticsearch/action/admin/cluster/migration/TransportGetFeatureUpgradeStatusAction.java b/server/src/main/java/org/elasticsearch/action/admin/cluster/migration/TransportGetFeatureUpgradeStatusAction.java
index 993a617455dd3..46cf7800445de 100644
--- a/server/src/main/java/org/elasticsearch/action/admin/cluster/migration/TransportGetFeatureUpgradeStatusAction.java
+++ b/server/src/main/java/org/elasticsearch/action/admin/cluster/migration/TransportGetFeatureUpgradeStatusAction.java
@@ -27,12 +27,10 @@
 import org.elasticsearch.upgrades.SingleFeatureMigrationResult;
 import org.elasticsearch.upgrades.SystemIndexMigrationTaskState;
 
-import java.util.Collection;
 import java.util.Comparator;
 import java.util.List;
 import java.util.Optional;
 import java.util.stream.Collectors;
-import java.util.stream.Stream;
 
 import static org.elasticsearch.action.admin.cluster.migration.GetFeatureUpgradeStatusResponse.UpgradeStatus.ERROR;
 import static org.elasticsearch.action.admin.cluster.migration.GetFeatureUpgradeStatusResponse.UpgradeStatus.IN_PROGRESS;
@@ -148,8 +146,8 @@ static List<GetFeatureUpgradeStatusResponse.IndexInfo> getIndexInfos(ClusterStat
         final String failedFeatureName = featureStatus == null ? null : featureStatus.getFailedIndexName();
         final Exception exception = featureStatus == null ? null : featureStatus.getException();
 
-        return Stream.of(feature.getIndexDescriptors(), feature.getAssociatedIndexDescriptors())
-            .flatMap(Collection::stream)
+        return feature.getIndexDescriptors()
+            .stream()
             .flatMap(descriptor -> descriptor.getMatchingIndices(state.metadata()).stream())
             .sorted(String::compareTo)
             .map(index -> state.metadata().index(index))