diff --git a/core/modules/edit/lib/Drupal/edit/Form/EditFieldForm.php b/core/modules/edit/lib/Drupal/edit/Form/EditFieldForm.php
index 6faa0c9..cd6fe8e 100644
--- a/core/modules/edit/lib/Drupal/edit/Form/EditFieldForm.php
+++ b/core/modules/edit/lib/Drupal/edit/Form/EditFieldForm.php
@@ -9,6 +9,8 @@
 
 use Drupal\Core\Entity\EntityInterface;
 use Drupal\user\TempStoreFactory;
+use Drupal\Core\Entity\EntityChangedInterface;
+use Drupal\Core\Language\Language;
 
 /**
  * Builds and process a form for editing a single entity field.
@@ -86,7 +88,30 @@ protected function init(array &$form_state, EntityInterface $entity, $field_name
    */
   public function validate(array $form, array &$form_state) {
     $entity = $this->buildEntity($form, $form_state);
-    field_attach_form_validate($entity, $form, $form_state, array('field_name' =>  $form_state['field_name']));
+    //field_attach_form_validate($entity, $form, $form_state, array('field_name' =>  $form_state['field_name']));
+
+    $changedFieldName = $this->getChangedFieldName($entity);
+
+    $violations = array();
+    foreach ($entity as $field_name => $field) {
+      if ((!empty($changedFieldName) && $field_name == $changedFieldName) || ($field_name == $form_state['field_name'])) {
+        $field_violations = $field->validate();
+        if (is_array($field_violations) && count($field_violations)) {
+          $violations = array_merge($violations, $field_violations);
+        }
+      }
+    }
+
+    if (count($violations)) {
+      // Place violations in $form_state.
+      $langcode = field_is_translatable($entity->entityType(), field_info_field($entity->entityType(), $field_name)) ? $entity->language()->id : Language::LANGCODE_NOT_SPECIFIED;
+      $field_state = field_form_get_state($form['#parents'], $field_name, $langcode, $form_state);
+      $field_state['constraint_violations'] = $field_violations;
+      field_form_set_state($form['#parents'], $field_name, $langcode, $form_state, $field_state);
+
+      // Map errors back to form elements.
+      field_invoke_method('flagErrors', _field_invoke_widget_target($form_state['form_display']), $entity, $form, $form_state, array('field_name' => $form_state['field_name']));
+    }
   }
 
   /**
@@ -161,4 +186,20 @@ protected function simplify(array &$form, array &$form_state) {
     }
   }
 
+  /**
+   * Find the field name for the field carrying the changed timestamp, if any.
+   *
+   * @param \Drupal\Core\Entity\EntityInterface $entity
+   *   The entity.
+   */
+  protected function getChangedFieldName(EntityInterface $entity) {
+    foreach ($entity as $field_name => $field) {
+      $definition = $field->getDefinition();
+      if (isset($definition['property_constraints']['value']['EntityChanged'])) {
+        return $field_name;
+      }
+    }
+    return NULL;
+  }
+
 }
diff --git a/core/modules/edit/lib/Drupal/edit/Tests/EditLoadingTest.php b/core/modules/edit/lib/Drupal/edit/Tests/EditLoadingTest.php
index d3e474c..631c936 100644
--- a/core/modules/edit/lib/Drupal/edit/Tests/EditLoadingTest.php
+++ b/core/modules/edit/lib/Drupal/edit/Tests/EditLoadingTest.php
@@ -222,6 +222,49 @@ function testUserWithPermission() {
   }
 
   /**
+   * Tests Edit with concurrent node / Edit use.
+   */
+  function testConcurrentEdit() {
+    $this->drupalLogin($this->editor_user);
+
+    $response = $this->retrieveFieldForm('node/1/body/und/full');
+    debug($response);
+    $ajax_commands = drupal_json_decode($response);
+
+    // Prepare form values for submission. drupalPostAJAX() is not suitable
+    // for handling pages with JSON responses, so we need our own solution
+    // here.
+    $form_tokens_found = preg_match('/\sname="form_token" value="([^"]+)"/', $ajax_commands[0]['data'], $token_match) && preg_match('/\sname="form_build_id" value="([^"]+)"/', $ajax_commands[0]['data'], $build_id_match);
+    $this->assertTrue($form_tokens_found, 'Form tokens found in output.');
+
+    if ($form_tokens_found) {
+      $edit = array();
+      $edit['form_id'] = 'edit_field_form';
+      $edit['form_token'] = $token_match[1];
+      $edit['form_build_id'] = $build_id_match[1];
+      $edit['body[und][0][summary]'] = '';
+      $edit['body[und][0][value]'] = '<p>Fine thanks.</p>';
+      $edit['body[und][0][format]'] = 'filtered_html';
+      $edit['op'] = t('Save');
+
+      // Save the node on the regular node edit form.
+      $this->drupalPost('node/1/edit', array(), t('Save'));
+      sleep(2);
+
+      // Submit field form and check response. Should throw a validation error
+      // because the node was changed in the meantime.
+      $response = $this->submitFieldForm('node/1/body/und/full', $edit);
+      debug($response);
+      $this->assertResponse(200);
+      $ajax_commands = drupal_json_decode($response);
+      debug($ajax_commands);
+      $this->assertIdentical(1, count($ajax_commands), 'The field form HTTP request results in one AJAX command.');
+      $this->assertIdentical('editFieldFormValidationErrors', $ajax_commands[0]['command'], 'The first AJAX command is an editFieldFormValidationErrors command.');
+      $this->assertTrue(strpos($ajax_commands[0]['data'], t('The copy of the content being edited is outdated. Reload the page to edit an up-to-date version.')), 'Error message returned to user.');
+    }
+  }
+
+  /**
    * Retrieve Edit metadata from the server. May also result in additional
    * JavaScript settings and CSS/JS being loaded.
    *