diff --git a/core/lib/Drupal/Core/Field/EntityReferenceFieldItemList.php b/core/lib/Drupal/Core/Field/EntityReferenceFieldItemList.php
index 2756730799..0bf5e152eb 100644
--- a/core/lib/Drupal/Core/Field/EntityReferenceFieldItemList.php
+++ b/core/lib/Drupal/Core/Field/EntityReferenceFieldItemList.php
@@ -4,6 +4,7 @@
 
 use Drupal\Core\Entity\ContentEntityInterface;
 use Drupal\Core\Entity\FieldableEntityInterface;
+use Drupal\Core\Entity\Plugin\DataType\EntityReference;
 use Drupal\Core\Form\FormStateInterface;
 
 /**
@@ -16,13 +17,20 @@ class EntityReferenceFieldItemList extends FieldItemList implements EntityRefere
    */
   public function getSerializationValue($deep_serialization) {
     // When performing a deep serialization then we overwrite the parent method
-    // in order to include the computed properties i.e. in the current case the
-    // referenced entity objects and flag them for deep serialization as well.
+    // in order to include the properties holding entities and flag the entities
+    // for deep serialization as well.
     if ($deep_serialization) {
       $values = $this->getValue(TRUE);
       foreach ($values as $delta => $item_values) {
-        if (isset($values[$delta]['entity']) && ($values[$delta]['entity'] instanceof ContentEntityInterface)) {
-          $values[$delta]['entity']->setDeepSerialization(TRUE);
+        /** @var \Drupal\Core\Field\FieldItemInterface $item */
+        $item = $this->get($delta);
+        foreach ($item_values as $property_name => $property_value) {
+          $property = $item->get($property_name);
+          if ($property instanceof EntityReference) {
+            if (isset($values[$delta][$property_name]) && ($values[$delta][$property_name] instanceof ContentEntityInterface)) {
+              $values[$delta][$property_name]->setDeepSerialization(TRUE);
+            }
+          }
         }
       }
     }