diff -u b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php
--- b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php
+++ b/core/lib/Drupal/Core/Field/Plugin/Field/FieldType/EntityReferenceItem.php
@@ -210,7 +210,7 @@
 
     // If there is an unsaved entity, return it as part of the field item values
     // to ensure idempotency of getValue() / setValue().
-    if ($include_computed || $this->hasNewEntity()) {
+    if (($include_computed && !$this->isEmpty()) || $this->hasNewEntity()) {
       $values['entity'] = $this->entity;
     }
     return $values;