diff --git a/src/Normalizer/FieldItemNormalizer.php b/src/Normalizer/FieldItemNormalizer.php
index 2066497..122dbdd 100644
--- a/src/Normalizer/FieldItemNormalizer.php
+++ b/src/Normalizer/FieldItemNormalizer.php
@@ -5,7 +5,6 @@ namespace Drupal\jsonapi_extras\Normalizer;
 use Drupal\Core\Cache\CacheableMetadata;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Drupal\Core\Field\FieldItemInterface;
-use Drupal\jsonapi\Normalizer\NormalizerBase;
 use Drupal\jsonapi\Normalizer\FieldItemNormalizer as JsonapiFieldItemNormalizer;
 use Drupal\jsonapi\Normalizer\Value\FieldItemNormalizerValue;
 use Drupal\jsonapi_extras\Plugin\ResourceFieldEnhancerManager;
@@ -14,7 +13,7 @@ use Symfony\Component\Serializer\SerializerInterface;
 /**
  * Converts the Drupal field structure to a JSON:API array structure.
  */
-class FieldItemNormalizer extends NormalizerBase {
+class FieldItemNormalizer extends JsonapiFieldItemNormalizer {
 
   /**
    * The interface or class that this Normalizer supports.
@@ -64,6 +63,10 @@ class FieldItemNormalizer extends NormalizerBase {
    * {@inheritdoc}
    */
   public function normalize($object, $format = NULL, array $context = []) {
+    if (!($context['resource_type'] instanceof JsonapiResourceConfig)) {
+      return parent::normalize($object, $format, $context);
+    }
+
     // First get the regular output.
     $normalized_output = $this->subject->normalize($object, $format, $context);
     // Then detect if there is any enhancer to be applied here.
diff --git a/src/ResourceType/ConfigurableResourceTypeRepository.php b/src/ResourceType/ConfigurableResourceTypeRepository.php
index e485fae..51f4797 100644
--- a/src/ResourceType/ConfigurableResourceTypeRepository.php
+++ b/src/ResourceType/ConfigurableResourceTypeRepository.php
@@ -121,6 +121,10 @@ class ConfigurableResourceTypeRepository extends ResourceTypeRepository {
     );
     $resource_config = $this->getResourceConfig($resource_config_id);
 
+    if ($resource_config instanceof NullJsonapiResourceConfig) {
+      return parent::createResourceType($entity_type, $bundle);
+    }
+
     // Create subclassed ResourceType object with the same parameters as the
     // parent implementation.
     $resource_type = new ConfigurableResourceType(