diff --git a/core/lib/Drupal/Core/Entity/ContentEntityStorageBase.php b/core/lib/Drupal/Core/Entity/ContentEntityStorageBase.php
index 610cda4..ae6574f 100644
--- a/core/lib/Drupal/Core/Entity/ContentEntityStorageBase.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityStorageBase.php
@@ -82,7 +82,7 @@ protected function doCreate(array $values) {
   /**
    * {@inheritdoc}
    */
-  public function createWithSampleValues($bundle = FALSE, array $values = [], $required_only = FALSE) {
+  public function createWithSampleValues($bundle = FALSE, array $values = []) {
     // ID and revision should never have sample values generated for them.
     $forbidden_keys = [
       $this->entityType->getKey('id'),
@@ -90,22 +90,28 @@ public function createWithSampleValues($bundle = FALSE, array $values = [], $req
     if ($revision_key = $this->entityType->getKey('revision')) {
       $forbidden_keys[] = $revision_key;
     }
-    if ($bundle && $bundle_key = $this->entityType->getKey('bundle')) {
-      $values[$bundle_key] = $bundle;
+    if ($bundle_key = $this->entityType->getKey('bundle')) {
+      if ($bundle) {
+        if (!array_key_exists($bundle, $this->entityManager->getBundleInfo($this->entityTypeId))) {
+          throw new EntityStorageException(sprintf("Missing entity bundle. The \"%s\" bundle does not exist", $bundle));
+        }
+        $values[$bundle_key] = $bundle;
+      }
+      // Bundle should not be autogenerated.
+      $forbidden_keys[] = $bundle_key;
     }
-    if ($published_key = $this->entityType->getKey('published')) {
-      $values[$published_key] = TRUE;
-    }
-    if ($status_key = $this->entityType->getKey('status')) {
-      $values[$status_key] = TRUE;
+
+    // Ensure that default_langcode is TRUE.
+    if ($default_langcode_key = $this->entityType->getKey('default_langcode')) {
+      $values[$default_langcode_key] = TRUE;
     }
+
     // Forbid sample generation on any keys whose values were submitted.
     $forbidden_keys = array_merge($forbidden_keys, array_keys($values));
     /** @var \Drupal\Core\Entity\FieldableEntityInterface $entity */
     $entity = $this->create($values);
     foreach ($entity as $field_name => $value) {
-      $definition = $entity->getFieldDefinition($field_name);
-      if (!in_array($field_name, $forbidden_keys, TRUE) && (!$required_only || ($definition && $definition->isRequired()))) {
+      if (!in_array($field_name, $forbidden_keys, TRUE)) {
         $entity->get($field_name)->generateSampleItems();
       }
     }
diff --git a/core/lib/Drupal/Core/Entity/ContentEntityStorageInterface.php b/core/lib/Drupal/Core/Entity/ContentEntityStorageInterface.php
index cd79530..eb979c7 100644
--- a/core/lib/Drupal/Core/Entity/ContentEntityStorageInterface.php
+++ b/core/lib/Drupal/Core/Entity/ContentEntityStorageInterface.php
@@ -23,6 +23,7 @@
    */
   public function createTranslation(ContentEntityInterface $entity, $langcode, array $values = []);
 
+
   /**
    * Creates an entity with sample field values.
    *
@@ -30,9 +31,6 @@ public function createTranslation(ContentEntityInterface $entity, $langcode, arr
    *   (optional) The entity bundle.
    * @param array $values
    *   (optional) Any default values to use during generation.
-   * @param bool $required_only
-   *   (optional) If TRUE, only create sample values for required fields.
-   *   Defaults to FALSE.
    *
    * @return \Drupal\Core\Entity\FieldableEntityInterface
    *   A fieldable content entity.
@@ -40,6 +38,6 @@ public function createTranslation(ContentEntityInterface $entity, $langcode, arr
    * @throws \Drupal\Core\Entity\EntityStorageException
    *   Thrown if the bundle does not exist or was needed but not specified.
    */
-  public function createWithSampleValues($bundle = FALSE, array $values = [], $required_only = FALSE);
+  public function createWithSampleValues($bundle = FALSE, array $values = []);
 
 }
diff --git a/core/lib/Drupal/Core/Entity/KeyValueStore/KeyValueContentEntityStorage.php b/core/lib/Drupal/Core/Entity/KeyValueStore/KeyValueContentEntityStorage.php
index 9510963..b3fc12d 100644
--- a/core/lib/Drupal/Core/Entity/KeyValueStore/KeyValueContentEntityStorage.php
+++ b/core/lib/Drupal/Core/Entity/KeyValueStore/KeyValueContentEntityStorage.php
@@ -21,7 +21,6 @@ public function createTranslation(ContentEntityInterface $entity, $langcode, arr
   /**
    * {@inheritdoc}
    */
-  public function createWithSampleValues($bundle = FALSE, array $values = [], $required_only = FALSE) {
-  }
+  public function createWithSampleValues($bundle = FALSE, array $values = []) {}
 
 }
diff --git a/core/lib/Drupal/Core/Field/FieldItemList.php b/core/lib/Drupal/Core/Field/FieldItemList.php
index 5d13a5e..4bfcbf9 100644
--- a/core/lib/Drupal/Core/Field/FieldItemList.php
+++ b/core/lib/Drupal/Core/Field/FieldItemList.php
@@ -260,8 +260,11 @@ public function view($display_options = []) {
   public function generateSampleItems($count = 1) {
     $field_definition = $this->getFieldDefinition();
     $field_type_class = $field_definition->getItemDefinition()->getClass();
+    $values = $this->getValue();
     for ($delta = 0; $delta < $count; $delta++) {
-      $values[$delta] = $field_type_class::generateSampleValue($field_definition);
+      if ($value = $field_type_class::generateSampleValue($field_definition)) {
+        $values[$delta] = $value;
+      }
     }
     $this->setValue($values);
   }
diff --git a/core/modules/content_moderation/src/Plugin/Field/ModerationStateFieldItemList.php b/core/modules/content_moderation/src/Plugin/Field/ModerationStateFieldItemList.php
index 4270a1f..b526363 100644
--- a/core/modules/content_moderation/src/Plugin/Field/ModerationStateFieldItemList.php
+++ b/core/modules/content_moderation/src/Plugin/Field/ModerationStateFieldItemList.php
@@ -153,7 +153,7 @@ protected function updateModeratedEntity($moderation_state_id) {
 
     // Change the entity's default revision flag and the publishing status only
     // if the new workflow state is a valid one.
-    if ($workflow->getTypePlugin()->hasState($moderation_state_id)) {
+    if ($workflow && $workflow->getTypePlugin()->hasState($moderation_state_id)) {
       /** @var \Drupal\content_moderation\ContentModerationState $current_state */
       $current_state = $workflow->getTypePlugin()->getState($moderation_state_id);
 
diff --git a/core/modules/path/src/Plugin/Field/FieldType/PathItem.php b/core/modules/path/src/Plugin/Field/FieldType/PathItem.php
index 9b5b67d..63c7a0d 100644
--- a/core/modules/path/src/Plugin/Field/FieldType/PathItem.php
+++ b/core/modules/path/src/Plugin/Field/FieldType/PathItem.php
@@ -149,7 +149,7 @@ public function postSave($update) {
    */
   public static function generateSampleValue(FieldDefinitionInterface $field_definition) {
     $random = new Random();
-    $values['alias'] = str_replace(' ', '-', strtolower($random->sentences(3)));
+    $values['alias'] = '/' . str_replace(' ', '-', strtolower($random->sentences(3)));
     return $values;
   }
 
diff --git a/core/tests/Drupal/KernelTests/Core/Entity/CreateSampleEntityTest.php b/core/tests/Drupal/KernelTests/Core/Entity/CreateSampleEntityTest.php
index b5bcd48..5bbce65 100644
--- a/core/tests/Drupal/KernelTests/Core/Entity/CreateSampleEntityTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Entity/CreateSampleEntityTest.php
@@ -2,7 +2,8 @@
 
 namespace Drupal\KernelTests\Core\Entity;
 
-use Drupal\Core\Entity\FieldableEntityInterface;
+use Drupal\Core\Entity\ContentEntityStorageInterface;
+use Drupal\Core\Entity\EntityInterface;
 use Drupal\KernelTests\KernelTestBase;
 use Drupal\node\Entity\NodeType;
 use Drupal\taxonomy\Entity\Vocabulary;
@@ -25,7 +26,21 @@ class CreateSampleEntityTest extends KernelTestBase {
   /**
    * {@inheritdoc}
    */
-  public static $modules = ['system', 'field', 'filter', 'text', 'file', 'user', 'node', 'comment', 'taxonomy'];
+  public static $modules = [
+    'system',
+    'field',
+    'filter',
+    'text',
+    'file',
+    'user',
+    'node',
+    'comment',
+    'taxonomy',
+    'menu_link_content',
+    'link',
+    'content_translation',
+    'language',
+  ];
 
   /**
    * {@inheritdoc}
@@ -33,6 +48,8 @@ class CreateSampleEntityTest extends KernelTestBase {
   protected function setUp() {
     parent::setup();
 
+    $this->installSchema('system', ['sequences']);
+
     $this->installEntitySchema('file');
     $this->installEntitySchema('user');
     $this->installEntitySchema('node');
@@ -42,6 +59,7 @@ protected function setUp() {
     $this->installEntitySchema('comment_type');
     $this->installEntitySchema('taxonomy_vocabulary');
     $this->installEntitySchema('taxonomy_term');
+    $this->installEntitySchema('menu_link_content');
     $this->entityTypeManager = $this->container->get('entity_type.manager');
     NodeType::create(['type' => 'article', 'name' => 'Article'])->save();
     NodeType::create(['type' => 'page', 'name' => 'Page'])->save();
@@ -55,31 +73,32 @@ protected function setUp() {
    */
   public function testSampleValueContentEntity() {
     foreach ($this->entityTypeManager->getDefinitions() as $entity_type_id => $definition) {
-      if ($definition->entityClassImplements(FieldableEntityInterface::class)) {
-        $label = $definition->getKey('label');
+      $entity_storage = $this->entityTypeManager->getStorage($entity_type_id);
+      if ($entity_storage instanceof ContentEntityStorageInterface) {
         $values = [];
-        if ($label) {
-          $title = $this->randomString();
-          $values[$label] = $title;
+        if ($label = $definition->getKey('label')) {
+          $values[$label] = $this->randomString();
         }
+
         // Create sample entities with bundles.
         if ($bundle_type = $definition->getBundleEntityType()) {
-          foreach ($this->entityTypeManager->getStorage($bundle_type)->loadMultiple() as $bundle) {
-            $entity = $this->entityTypeManager->getStorage($entity_type_id)->createWithSampleValues($bundle->id(), $values);
-            $violations = $entity->validate();
-            $this->assertCount(0, $violations);
-            if ($label) {
-              $this->assertEquals($title, $entity->label());
-            }
-          }
+          $bundles = array_map(function (EntityInterface $entity_type) {
+            return $entity_type->id();
+          }, $this->entityTypeManager->getStorage($bundle_type)->loadMultiple());
         }
         // Create sample entities without bundles.
         else {
-          $entity = $this->entityTypeManager->getStorage($entity_type_id)->createWithSampleValues(FALSE, $values);
+          $bundles = [FALSE];
+        }
+        foreach ($bundles as $bundle) {
+          $entity = $entity_storage->createWithSampleValues($bundle, $values);
+          $entity->save();
+          $entity_storage->resetCache([$entity->id()]);
+          $entity = $entity_storage->load($entity->id());
           $violations = $entity->validate();
-          $this->assertCount(0, $violations);
+          $this->assertCount(0, $violations, (string) $violations);
           if ($label) {
-            $this->assertEquals($title, $entity->label());
+            $this->assertEquals($values[$label], $entity->label());
           }
         }
       }
diff --git a/core/tests/Drupal/KernelTests/Core/Form/FormElementTitleTest.php b/core/tests/Drupal/KernelTests/Core/Form/FormElementTitleTest.php
index f291e0b..4ffa6a4 100644
--- a/core/tests/Drupal/KernelTests/Core/Form/FormElementTitleTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Form/FormElementTitleTest.php
@@ -345,7 +345,7 @@ protected function createEntities() {
       if ($entity_storage instanceof ContentEntityStorageInterface) {
         $bundle_entity_type_id = $entity_type->getBundleEntityType();
         $bundle = $bundle_entity_type_id ? $entities[$bundle_entity_type_id]->id() : FALSE;
-        $entity = $entity_storage->createWithSampleValues($bundle, $entity_values[$entity_type_id], TRUE);
+        $entity = $entity_storage->createWithSampleValues($bundle, $entity_values[$entity_type_id]);
       }
       else {
         $values = $entity_values[$entity_type_id];