src/Normalizer/ConfigEntityNormalizer.php               | 17 +++++++----------
 .../JsonApiDocumentTopLevelNormalizerTest.php           |  4 ++--
 .../src/Unit/Normalizer/ConfigEntityNormalizerTest.php  |  4 +---
 3 files changed, 10 insertions(+), 15 deletions(-)

diff --git a/src/Normalizer/ConfigEntityNormalizer.php b/src/Normalizer/ConfigEntityNormalizer.php
index 5d97676..3b8d06c 100644
--- a/src/Normalizer/ConfigEntityNormalizer.php
+++ b/src/Normalizer/ConfigEntityNormalizer.php
@@ -45,17 +45,14 @@ class ConfigEntityNormalizer extends EntityNormalizer {
    */
   protected function serializeField($field, array $context, $format) {
     $output = $this->serializer->normalize($field, $format, $context);
-    if (is_array($output)) {
-      $output = new FieldNormalizerValue(
-        [new FieldItemNormalizerValue($output)],
-        1
-      );
-      $output->setPropertyType('attributes');
-      return $output;
+    if (!is_array($output)) {
+      $output = [$output];
     }
-    $field instanceof Relationship ?
-      $output->setPropertyType('relationships') :
-      $output->setPropertyType('attributes');
+    $output = new FieldNormalizerValue(
+      [new FieldItemNormalizerValue($output)],
+      1
+    );
+    $output->setPropertyType('attributes');
     return $output;
   }
 
diff --git a/tests/src/Kernel/Normalizer/JsonApiDocumentTopLevelNormalizerTest.php b/tests/src/Kernel/Normalizer/JsonApiDocumentTopLevelNormalizerTest.php
index 6d1afc9..4f494cf 100644
--- a/tests/src/Kernel/Normalizer/JsonApiDocumentTopLevelNormalizerTest.php
+++ b/tests/src/Kernel/Normalizer/JsonApiDocumentTopLevelNormalizerTest.php
@@ -264,7 +264,7 @@ class JsonApiDocumentTopLevelNormalizerTest extends JsonapiKernelTestBase {
     // Make sure that the cache tags for the includes and the requested entities
     // are bubbling as expected.
     $this->assertSame(
-      ['file:1', 'node:1', 'taxonomy_term:1', 'taxonomy_term:2'],
+      ['file:1', 'node:1', 'taxonomy_term:1', 'taxonomy_term:2', 'user:1'],
       $response->getCacheableMetadata()->getCacheTags()
     );
     $this->assertSame(
@@ -362,7 +362,7 @@ class JsonApiDocumentTopLevelNormalizerTest extends JsonapiKernelTestBase {
     // Make sure that the cache tags for the includes and the requested entities
     // are bubbling as expected.
     $this->assertSame(
-      ['node:1', 'taxonomy_term:1', 'taxonomy_term:2'],
+      ['node:1', 'taxonomy_term:1', 'taxonomy_term:2', 'user:1'],
       $response->getCacheableMetadata()->getCacheTags()
     );
   }
diff --git a/tests/src/Unit/Normalizer/ConfigEntityNormalizerTest.php b/tests/src/Unit/Normalizer/ConfigEntityNormalizerTest.php
index 732dca0..bcbf144 100644
--- a/tests/src/Unit/Normalizer/ConfigEntityNormalizerTest.php
+++ b/tests/src/Unit/Normalizer/ConfigEntityNormalizerTest.php
@@ -8,7 +8,6 @@ use Drupal\jsonapi\ResourceType\ResourceType;
 use Drupal\jsonapi\ResourceType\ResourceTypeRepository;
 use Drupal\jsonapi\Normalizer\ConfigEntityNormalizer;
 use Drupal\jsonapi\LinkManager\LinkManager;
-use Drupal\jsonapi\Normalizer\ScalarNormalizer;
 use Drupal\Tests\UnitTestCase;
 use Prophecy\Argument;
 use Symfony\Component\Serializer\Serializer;
@@ -42,8 +41,7 @@ class ConfigEntityNormalizerTest extends UnitTestCase {
       $this->prophesize(EntityTypeManagerInterface::class)->reveal()
     );
 
-    $normalizers = [new ScalarNormalizer()];
-    $serializer = new Serializer($normalizers, []);
+    $serializer = new Serializer([], []);
     $this->normalizer->setSerializer($serializer);
   }