diff -u b/core/lib/Drupal/Core/Entity/ContentEntityBase.php b/core/lib/Drupal/Core/Entity/ContentEntityBase.php
--- b/core/lib/Drupal/Core/Entity/ContentEntityBase.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityBase.php
@@ -1109,18 +1109,17 @@
 
     $values = $this->values;
     $this->values = &$values;
-    unset($values);
 
-    foreach ($this->fields as $name => $values) {
+    foreach ($this->fields as $name => $fields_by_langcode) {
       $this->fields[$name] = [];
       // Untranslatable fields may have multiple references for the same field
       // object keyed by language. To avoid creating different field objects
       // we retain just the original value, as references will be recreated
       // later as needed.
-      if (!$definitions[$name]->isTranslatable() && count($values) > 1) {
-        $values = array_intersect_key($values, [LanguageInterface::LANGCODE_DEFAULT => TRUE]);
+      if (!$definitions[$name]->isTranslatable() && count($fields_by_langcode) > 1) {
+        $fields_by_langcode = array_intersect_key($fields_by_langcode, [LanguageInterface::LANGCODE_DEFAULT => TRUE]);
       }
-      foreach ($values as $langcode => $items) {
+      foreach ($fields_by_langcode as $langcode => $items) {
         $this->fields[$name][$langcode] = clone $items;
         $this->fields[$name][$langcode]->setContext($name, $this->getTranslation($langcode)->getTypedData());
       }