diff --git a/src/MultiversionManager.php b/src/MultiversionManager.php
index 1acffb8..c9f8c08 100644
--- a/src/MultiversionManager.php
+++ b/src/MultiversionManager.php
@@ -380,6 +380,21 @@ class MultiversionManager implements MultiversionManagerInterface, ContainerAwar
   }
 
   /**
+   * @param unknown $normalized_entity
+   */
+  protected function filterNormalizedEntity(&$normalized_entity){
+    foreach ($normalized_entity as $key => &$value) {
+      if ($key{0} == '_') {
+        unset($normalized_entity[$key]);
+      }else{
+        if(is_array($value)){
+          $this->filterNormalizedEntity($value);
+        }
+      }
+    }
+  }
+
+  /**
    * {@inheritdoc}
    */
   public function newRevisionId(ContentEntityInterface $entity, $index = 0) {
@@ -389,11 +404,7 @@ class MultiversionManager implements MultiversionManagerInterface, ContainerAwar
     // necessary) to identify in which format to return the normalized entity.
     $normalized_entity = $this->serializer->normalize($entity, NULL, ['new_revision_id' => TRUE]);
     // Remove fields internal to the multiversion system.
-    foreach ($normalized_entity as $key => $value) {
-      if ($key{0} == '_') {
-        unset($normalized_entity[$key]);
-      }
-    }
+    $this->filterNormalizedEntity($normalized_entity);
     // The terms being serialized are:
     // - deleted
     // - old sequence ID (@todo: {@link https://www.drupal.org/node/2597341