diff -u b/core/lib/Drupal/Core/Entity/Plugin/Validation/Constraint/ValidReferenceConstraintValidator.php b/core/lib/Drupal/Core/Entity/Plugin/Validation/Constraint/ValidReferenceConstraintValidator.php
--- b/core/lib/Drupal/Core/Entity/Plugin/Validation/Constraint/ValidReferenceConstraintValidator.php
+++ b/core/lib/Drupal/Core/Entity/Plugin/Validation/Constraint/ValidReferenceConstraintValidator.php
@@ -6,6 +6,7 @@
 use Drupal\Core\Entity\EntityReferenceSelection\SelectionPluginManagerInterface;
 use Drupal\Core\Entity\EntityReferenceSelection\SelectionWithAutocreateInterface;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\Entity\FieldableEntityInterface;
 use Drupal\Core\Field\EntityReferenceFieldItemList;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\Validator\Constraint;
@@ -120,7 +121,23 @@
           if (isset($entity->recursiveValidationRunning)) {
             continue;
           }
-          $violations = $entity->getTypedData()->validate();
+
+          if ($entity instanceof FieldableEntityInterface) {
+            // If the referenced entity has been validated somewhere else then
+            // we don't need to validate it again, as code validating the entity
+            // and leaving the validated flag set to TRUE is required of taking
+            // care of the errors.
+            if ($entity->isValidated()) {
+              continue;
+            }
+            else {
+              $violations = $entity->validate();
+            }
+          }
+          else {
+            $violations = $entity->getTypedData()->validate();
+          }
+
           if ($violations->count() != 0) {
             // Concatenate the violations to show them as a single violation.
             $reasons = [];
only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/Entity/ContentEntityBase.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityBase.php
@@ -464,6 +464,21 @@ public function validate() {
     return new EntityConstraintViolationList($this, iterator_to_array($violations));
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function isValidated() {
+    return $this->validated;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setValidated($validated) {
+    $this->validated = $validated;
+    return $this;
+  }
+
   /**
    * {@inheritdoc}
    */
only in patch2:
unchanged:
--- a/core/lib/Drupal/Core/Entity/FieldableEntityInterface.php
+++ b/core/lib/Drupal/Core/Entity/FieldableEntityInterface.php
@@ -212,12 +212,36 @@ public function onChange($field_name);
   /**
    * Validates the currently set values.
    *
+   * Note that by calling this method the entity will be flagged as validated
+   * and validation logic might be skipped, because ::isValidated() would return
+   * TRUE. To prevent this the validated flag could be reset by calling
+   * ::setValidated(FALSE).
+   *
    * @return \Drupal\Core\Entity\EntityConstraintViolationListInterface
    *   A list of constraint violations. If the list is empty, validation
    *   succeeded.
    */
   public function validate();
 
+  /**
+   * Checks whether the entity has been validated.
+   *
+   * @return bool
+   *   TRUE if the entity has been validated, FALSE if not.
+   */
+  public function isValidated();
+
+  /**
+   * Sets the validated flag.
+   *
+   * @param bool $validated
+   *   If set to TRUE the entity will be flagged as validated, otherwise as not
+   *   validated.
+   *
+   * @return $this
+   */
+  public function setValidated($validated);
+
   /**
    * Checks whether entity validation is required before saving the entity.
    *