diff --git a/core/esmf-aspect-model-document-generators/src/main/java/org/eclipse/esmf/aspectmodel/generator/openapi/AspectModelOpenApiGenerator.java b/core/esmf-aspect-model-document-generators/src/main/java/org/eclipse/esmf/aspectmodel/generator/openapi/AspectModelOpenApiGenerator.java
index cf5c9daf2..d2f512930 100644
--- a/core/esmf-aspect-model-document-generators/src/main/java/org/eclipse/esmf/aspectmodel/generator/openapi/AspectModelOpenApiGenerator.java
+++ b/core/esmf-aspect-model-document-generators/src/main/java/org/eclipse/esmf/aspectmodel/generator/openapi/AspectModelOpenApiGenerator.java
@@ -617,6 +617,8 @@ private static ObjectNode mergeObjectNode( final ObjectNode node, final ObjectNo
                   node.set( key, mergeObjectNode( (ObjectNode) resultValue, (ObjectNode) value ) );
                } else if ( resultValue.isArray() && value.isArray() ) {
                   node.set( key, mergeArrayNode( (ArrayNode) resultValue, (ArrayNode) value ) );
+               } else {
+                  node.set( key, value );
                }
             } else {
                node.set( key, value );
diff --git a/core/esmf-aspect-model-document-generators/src/main/java/org/eclipse/esmf/aspectmodel/generator/openapi/OpenApiSchemaGenerationConfig.java b/core/esmf-aspect-model-document-generators/src/main/java/org/eclipse/esmf/aspectmodel/generator/openapi/OpenApiSchemaGenerationConfig.java
index 3df6774f1..39863277b 100644
--- a/core/esmf-aspect-model-document-generators/src/main/java/org/eclipse/esmf/aspectmodel/generator/openapi/OpenApiSchemaGenerationConfig.java
+++ b/core/esmf-aspect-model-document-generators/src/main/java/org/eclipse/esmf/aspectmodel/generator/openapi/OpenApiSchemaGenerationConfig.java
@@ -16,7 +16,6 @@
 import static org.eclipse.esmf.aspectmodel.generator.openapi.AspectModelOpenApiGenerator.ObjectNodeExtension.getter;
 
 import java.util.Locale;
-import java.util.Optional;
 
 import org.eclipse.esmf.aspectmodel.generator.GenerationConfig;
 
@@ -67,21 +66,20 @@ public record OpenApiSchemaGenerationConfig(
    }
 
    public ObjectNode queriesTemplate() {
-      return Optional.ofNullable( template )
-            .map( getter( "paths" ) )
-            .map( getter( QUERIES_TEMPLATE_PATH ) )
-            .orElse( null );
+      if ( template == null ) {
+         return null;
+      }
+
+      final ObjectNode objectNode = getter( "paths" ).apply( template );
+      return getter( QUERIES_TEMPLATE_PATH ).apply( objectNode );
    }
 
    public ObjectNode documentTemplate() {
-      return Optional.ofNullable( template )
-            .map( ObjectNode::deepCopy )
-            .map( doc -> {
-               Optional.of( doc ).map( getter( "paths" ) ).ifPresent(
-                     paths -> paths.remove( QUERIES_TEMPLATE_PATH )
-               );
-               return doc;
-            } )
-            .orElse( null );
+      if ( template == null ) {
+         return null;
+      }
+      final ObjectNode objectNode = template.deepCopy();
+      getter( "paths" ).apply( objectNode ).remove( QUERIES_TEMPLATE_PATH );
+      return objectNode;
    }
 }
diff --git a/core/esmf-aspect-model-document-generators/src/test/java/org/eclipse/esmf/aspectmodel/generator/openapi/AspectModelOpenApiGeneratorTest.java b/core/esmf-aspect-model-document-generators/src/test/java/org/eclipse/esmf/aspectmodel/generator/openapi/AspectModelOpenApiGeneratorTest.java
index c898731d9..45f945434 100644
--- a/core/esmf-aspect-model-document-generators/src/test/java/org/eclipse/esmf/aspectmodel/generator/openapi/AspectModelOpenApiGeneratorTest.java
+++ b/core/esmf-aspect-model-document-generators/src/test/java/org/eclipse/esmf/aspectmodel/generator/openapi/AspectModelOpenApiGeneratorTest.java
@@ -254,6 +254,28 @@ void testValidParameter() throws IOException {
       } );
    }
 
+   @Test
+   void testValidTemplate() throws IOException {
+      final Aspect aspect = TestResources.load( TestAspect.ASPECT_WITHOUT_SEE_ATTRIBUTE ).aspect();
+      final OpenApiSchemaGenerationConfig config = OpenApiSchemaGenerationConfigBuilder.builder()
+            .useSemanticVersion( true )
+            .baseUrl( TEST_BASE_URL )
+            .resourcePath( TEST_RESOURCE_PATH )
+            .template( getTemplateParameter() )
+            .build();
+      final JsonNode json = apiJsonGenerator.apply( aspect, config ).getContent();
+      final SwaggerParseResult result = new OpenAPIParser().readContents( json.toString(), null, null );
+      assertThat( result.getMessages() ).isEmpty();
+
+      final OpenAPI openApi = result.getOpenAPI();
+      assertThat( openApi.getPaths().values().stream().findFirst().get().getGet().getResponses().get( "400" ).get$ref() )
+            .isEqualTo( "./core-api.yaml#/components/responses/ClientError" );
+      assertThat( openApi.getPaths().values().stream().findFirst().get().getGet().getResponses().get( "401" ).get$ref() )
+            .isEqualTo( "./core-api.yaml#/components/responses/Unauthorized" );
+      assertThat( openApi.getPaths().values().stream().findFirst().get().getGet().getResponses().get( "403" ).get$ref() )
+            .isEqualTo( "./core-api.yaml#/components/responses/Forbidden" );
+   }
+
    @Test
    void testInValidParameterName() throws IOException {
       final ListAppender<ILoggingEvent> logAppender = new ListAppender<>();
@@ -495,11 +517,11 @@ void testAspectWithOperationWithSeeAttribute() {
       final SwaggerParseResult result = new OpenAPIParser().readContents( json.toString(), null, null );
       final OpenAPI openApi = result.getOpenAPI();
       assertThat(
-            ((Schema) openApi.getComponents().getSchemas().get( "testOperation" ).getAllOf()
-                  .get( 1 )).getProperties() ).doesNotContainKey(
+            ( (Schema) openApi.getComponents().getSchemas().get( "testOperation" ).getAllOf()
+                  .get( 1 ) ).getProperties() ).doesNotContainKey(
             "params" );
-      assertThat( ((Schema) openApi.getComponents().getSchemas().get( "testOperationTwo" ).getAllOf()
-            .get( 1 )).getProperties() ).doesNotContainKey( "params" );
+      assertThat( ( (Schema) openApi.getComponents().getSchemas().get( "testOperationTwo" ).getAllOf()
+            .get( 1 ) ).getProperties() ).doesNotContainKey( "params" );
    }
 
    @Test
@@ -635,8 +657,8 @@ void testAspectWithCommentForSeeAttributes() {
       assertThat( openApi.getSpecVersion() ).isEqualTo( SpecVersion.V31 );
       assertThat( openApi.getComponents().getSchemas().get( "AspectWithCollection" ).get$comment() ).isEqualTo(
             "See: http://example.com/" );
-      assertThat( ((Schema) openApi.getComponents().getSchemas().get( "AspectWithCollection" ).getProperties()
-            .get( "testProperty" )).get$comment() )
+      assertThat( ( (Schema) openApi.getComponents().getSchemas().get( "AspectWithCollection" ).getProperties()
+            .get( "testProperty" ) ).get$comment() )
             .isEqualTo( "See: http://example.com/, http://example.com/me" );
       assertThat( openApi.getComponents().getSchemas().get( "TestCollection" ).get$comment() )
             .isEqualTo( "See: http://example.com/" );
@@ -766,4 +788,10 @@ private ObjectNode getTestParameter() throws IOException {
       final String inputString = IOUtils.toString( inputStream, StandardCharsets.UTF_8 );
       return (ObjectNode) OBJECT_MAPPER.readTree( inputString );
    }
+
+   private ObjectNode getTemplateParameter() throws IOException {
+      final InputStream inputStream = getClass().getResourceAsStream( "/openapi/open-api-error-template.yaml" );
+      final String inputString = IOUtils.toString( inputStream, StandardCharsets.UTF_8 );
+      return (ObjectNode) new YAMLMapper().readTree( inputString );
+   }
 }
diff --git a/core/esmf-aspect-model-document-generators/src/test/resources/openapi/open-api-error-template.yaml b/core/esmf-aspect-model-document-generators/src/test/resources/openapi/open-api-error-template.yaml
new file mode 100644
index 000000000..e1f91e666
--- /dev/null
+++ b/core/esmf-aspect-model-document-generators/src/test/resources/openapi/open-api-error-template.yaml
@@ -0,0 +1,10 @@
+paths:
+  __DEFAULT_QUERIES_TEMPLATE__:
+    get:
+      responses:
+        '400':
+          $ref: "core-api.yaml#/components/responses/ClientError"
+        '401':
+          $ref: "core-api.yaml#/components/responses/Unauthorized"
+        '403':
+          $ref: "core-api.yaml#/components/responses/Forbidden"
\ No newline at end of file