diff --git a/client/rest-high-level/src/main/java/org/elasticsearch/client/rollup/RollableIndexCaps.java b/client/rest-high-level/src/main/java/org/elasticsearch/client/rollup/RollableIndexCaps.java
index cf849e38dd0..8e0bea0996b 100644
--- a/client/rest-high-level/src/main/java/org/elasticsearch/client/rollup/RollableIndexCaps.java
+++ b/client/rest-high-level/src/main/java/org/elasticsearch/client/rollup/RollableIndexCaps.java
@@ -44,7 +44,7 @@ public class RollableIndexCaps implements ToXContentFragment {
     public static final Function<String, ConstructingObjectParser<RollableIndexCaps, Void>> PARSER = indexName -> {
         @SuppressWarnings("unchecked")
         ConstructingObjectParser<RollableIndexCaps, Void> p
-            = new ConstructingObjectParser<>(indexName,
+            = new ConstructingObjectParser<>(indexName, true,
             a -> new RollableIndexCaps(indexName, (List<RollupJobCaps>) a[0]));
 
         p.declareObjectArray(ConstructingObjectParser.constructorArg(), RollupJobCaps.PARSER::apply,
diff --git a/client/rest-high-level/src/main/java/org/elasticsearch/client/rollup/RollupJobCaps.java b/client/rest-high-level/src/main/java/org/elasticsearch/client/rollup/RollupJobCaps.java
index 7ba1aaa4d7c..15161069f73 100644
--- a/client/rest-high-level/src/main/java/org/elasticsearch/client/rollup/RollupJobCaps.java
+++ b/client/rest-high-level/src/main/java/org/elasticsearch/client/rollup/RollupJobCaps.java
@@ -33,7 +33,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
-import java.util.function.Function;
+import java.util.stream.Collectors;
 
 /**
  * Represents the Rollup capabilities for a specific job on a single rollup index
@@ -45,15 +45,12 @@ public class RollupJobCaps implements ToXContentObject {
     private static final ParseField FIELDS = new ParseField("fields");
     private static final String NAME = "rollup_job_caps";
 
-    public static final ConstructingObjectParser<RollupJobCaps, Void> PARSER = new ConstructingObjectParser<>(NAME,
+    public static final ConstructingObjectParser<RollupJobCaps, Void> PARSER = new ConstructingObjectParser<>(NAME, true,
         a -> {
             @SuppressWarnings("unchecked")
             List<Tuple<String, RollupFieldCaps>> caps = (List<Tuple<String, RollupFieldCaps>>) a[3];
-            if (caps.isEmpty()) {
-                return new RollupJobCaps((String) a[0], (String) a[1], (String) a[2], Collections.emptyMap());
-            }
-            Map<String, RollupFieldCaps> mapCaps = new HashMap<>(caps.size());
-            caps.forEach(c -> mapCaps.put(c.v1(), c.v2()));
+            Map<String, RollupFieldCaps> mapCaps =
+                new HashMap<>(caps.stream().collect(Collectors.toMap(Tuple::v1, Tuple::v2)));
             return new RollupJobCaps((String) a[0], (String) a[1], (String) a[2], mapCaps);
         });
 
@@ -140,16 +137,6 @@ public class RollupJobCaps implements ToXContentObject {
         private static final String NAME = "rollup_field_caps";
         private final List<Map<String, Object>> aggs;
 
-        public static final Function<String, ConstructingObjectParser<RollupFieldCaps, Void>> PARSER = fieldName -> {
-            @SuppressWarnings("unchecked")
-            ConstructingObjectParser<RollupFieldCaps, Void> parser
-                = new ConstructingObjectParser<>(NAME, a -> new RollupFieldCaps((List<Map<String, Object>>) a[0]));
-
-            parser.declareObjectArray(ConstructingObjectParser.constructorArg(),
-                (p, c) -> p.map(), new ParseField(fieldName));
-            return parser;
-        };
-
         RollupFieldCaps(final List<Map<String, Object>> aggs) {
             this.aggs = Collections.unmodifiableList(Objects.requireNonNull(aggs));
         }
@@ -170,13 +157,12 @@ public class RollupJobCaps implements ToXContentObject {
             List<Map<String, Object>> aggs = new ArrayList<>();
             if (parser.nextToken().equals(XContentParser.Token.START_ARRAY)) {
                 while (parser.nextToken().equals(XContentParser.Token.START_OBJECT)) {
-                    aggs.add(Collections.unmodifiableMap(parser.map()));
+                    aggs.add(parser.map());
                 }
             }
-            return new RollupFieldCaps(Collections.unmodifiableList(aggs));
+            return new RollupFieldCaps(aggs);
         }
 
-
         @Override
         public boolean equals(Object other) {
             if (this == other) {
diff --git a/client/rest-high-level/src/test/java/org/elasticsearch/client/rollup/GetRollupCapsResponseTests.java b/client/rest-high-level/src/test/java/org/elasticsearch/client/rollup/GetRollupCapsResponseTests.java
index a728b65cf64..a9c3a59faf5 100644
--- a/client/rest-high-level/src/test/java/org/elasticsearch/client/rollup/GetRollupCapsResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/elasticsearch/client/rollup/GetRollupCapsResponseTests.java
@@ -23,6 +23,7 @@ import org.elasticsearch.common.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Map;
+import java.util.function.Predicate;
 
 public class GetRollupCapsResponseTests extends RollupCapsResponseTestCase<GetRollupCapsResponse> {
 
@@ -40,6 +41,15 @@ public class GetRollupCapsResponseTests extends RollupCapsResponseTestCase<GetRo
         builder.endObject();
     }
 
+    @Override
+    protected Predicate<String> randomFieldsExcludeFilter() {
+        return (field) ->
+            // base cannot have extra things in it
+            "".equals(field)
+            // the field list expects to be a nested object of a certain type
+            || field.contains("fields");
+    }
+
     @Override
     protected GetRollupCapsResponse fromXContent(XContentParser parser) throws IOException {
         return GetRollupCapsResponse.fromXContent(parser);
diff --git a/client/rest-high-level/src/test/java/org/elasticsearch/client/rollup/GetRollupIndexCapsResponseTests.java b/client/rest-high-level/src/test/java/org/elasticsearch/client/rollup/GetRollupIndexCapsResponseTests.java
index afd0e54f92b..20e29aef0df 100644
--- a/client/rest-high-level/src/test/java/org/elasticsearch/client/rollup/GetRollupIndexCapsResponseTests.java
+++ b/client/rest-high-level/src/test/java/org/elasticsearch/client/rollup/GetRollupIndexCapsResponseTests.java
@@ -23,6 +23,7 @@ import org.elasticsearch.common.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Map;
+import java.util.function.Predicate;
 
 public class GetRollupIndexCapsResponseTests extends RollupCapsResponseTestCase<GetRollupIndexCapsResponse> {
 
@@ -40,6 +41,15 @@ public class GetRollupIndexCapsResponseTests extends RollupCapsResponseTestCase<
         builder.endObject();
     }
 
+    @Override
+    protected Predicate<String> randomFieldsExcludeFilter() {
+        return (field) ->
+            // base cannot have extra things in it
+            "".equals(field)
+                // the field list expects to be a nested object of a certain type
+                || field.contains("fields");
+    }
+
     @Override
     protected GetRollupIndexCapsResponse fromXContent(XContentParser parser) throws IOException {
         return GetRollupIndexCapsResponse.fromXContent(parser);
diff --git a/client/rest-high-level/src/test/java/org/elasticsearch/client/rollup/RollupCapsResponseTestCase.java b/client/rest-high-level/src/test/java/org/elasticsearch/client/rollup/RollupCapsResponseTestCase.java
index 6d1c0359d17..cdc4280dbff 100644
--- a/client/rest-high-level/src/test/java/org/elasticsearch/client/rollup/RollupCapsResponseTestCase.java
+++ b/client/rest-high-level/src/test/java/org/elasticsearch/client/rollup/RollupCapsResponseTestCase.java
@@ -25,6 +25,7 @@ import org.elasticsearch.client.rollup.job.config.MetricConfig;
 import org.elasticsearch.client.rollup.job.config.RollupJobConfig;
 import org.elasticsearch.client.rollup.job.config.RollupJobConfigTests;
 import org.elasticsearch.client.rollup.job.config.TermsGroupConfig;
+import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.search.aggregations.bucket.histogram.DateHistogramAggregationBuilder;
@@ -40,6 +41,7 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.function.Predicate;
 import java.util.stream.Collectors;
 
 import static java.util.Collections.singletonMap;
@@ -55,15 +57,23 @@ abstract class RollupCapsResponseTestCase<T> extends ESTestCase {
 
     protected abstract T fromXContent(XContentParser parser) throws IOException;
 
+    protected Predicate<String> randomFieldsExcludeFilter() {
+        return field -> false;
+    }
+
+    protected String[] shuffleFieldsExceptions() {
+        return Strings.EMPTY_ARRAY;
+    }
+
     public void testFromXContent() throws IOException {
         xContentTester(
             this::createParser,
             this::createTestInstance,
             this::toXContent,
             this::fromXContent)
-            .supportsUnknownFields(false)
-            .randomFieldsExcludeFilter(field ->
-                field.endsWith("job_id"))
+            .supportsUnknownFields(true)
+            .randomFieldsExcludeFilter(randomFieldsExcludeFilter())
+            .shuffleFieldsExceptions(shuffleFieldsExceptions())
             .test();
     }