diff --git a/core/lib/Drupal/Core/Field/Entity/BaseFieldOverride.php b/core/lib/Drupal/Core/Field/Entity/BaseFieldOverride.php
index 9fbe75c..b6b2a3c 100644
--- a/core/lib/Drupal/Core/Field/Entity/BaseFieldOverride.php
+++ b/core/lib/Drupal/Core/Field/Entity/BaseFieldOverride.php
@@ -154,8 +154,12 @@ protected function getBaseFieldDefinition() {
    *   BaseFieldOverride::allowBundleRename() has not been called.
    */
   public function preSave(EntityStorageInterface $storage) {
-    // Set the default instance settings.
-    $this->settings += \Drupal::service('plugin.manager.field.field_type')->getDefaultFieldSettings($this->getType());
+    // Filter out unknown settings and make sure all settings are present, so
+    // that a complete field definition is passed to the various hooks and
+    // written to config.
+    $field_type_manager = \Drupal::service('plugin.manager.field.field_type');
+    $default_settings = $field_type_manager->getDefaultFieldSettings($this->getType());
+    $this->settings = array_intersect_key($this->settings, $default_settings) + $default_settings;
 
     // Call the parent's presave method to perform validate and calculate
     // dependencies.
diff --git a/core/lib/Drupal/Core/Field/FieldConfigBase.php b/core/lib/Drupal/Core/Field/FieldConfigBase.php
index eaba0f9..7f7e6be 100644
--- a/core/lib/Drupal/Core/Field/FieldConfigBase.php
+++ b/core/lib/Drupal/Core/Field/FieldConfigBase.php
@@ -270,15 +270,6 @@ public function postCreate(EntityStorageInterface $storage) {
   /**
    * {@inheritdoc}
    */
-  public function preSave(EntityStorageInterface $storage) {
-    // Filter out unknown settings.
-    $default_settings = $this->getFieldStorageDefinition()->getSettings();
-    $this->settings = array_intersect_key($this->settings, $default_settings);
-  }
-
-  /**
-   * {@inheritdoc}
-   */
   public function postSave(EntityStorageInterface $storage, $update = TRUE) {
     // Clear the cache.
     $this->entityManager()->clearCachedFieldDefinitions();
diff --git a/core/modules/field/src/Entity/FieldConfig.php b/core/modules/field/src/Entity/FieldConfig.php
index 87f4400..a8d9c0a 100644
--- a/core/modules/field/src/Entity/FieldConfig.php
+++ b/core/modules/field/src/Entity/FieldConfig.php
@@ -138,9 +138,13 @@ public function preSave(EntityStorageInterface $storage) {
 
     $storage_definition = $this->getFieldStorageDefinition();
 
+    // Filter out unknown settings and make sure all settings are present, so
+    // that a complete field definition is passed to the various hooks and
+    // written to config.
+    $default_settings = $field_type_manager->getDefaultFieldSettings($storage_definition->type);
+    $this->settings = array_intersect_key($this->settings, $default_settings) + $default_settings;
+
     if ($this->isNew()) {
-      // Set the default field settings.
-      $this->settings += $field_type_manager->getDefaultFieldSettings($storage_definition->type);
       // Notify the entity storage.
       $entity_manager->getStorage($this->entity_type)->onFieldDefinitionCreate($this);
     }
@@ -155,8 +159,6 @@ public function preSave(EntityStorageInterface $storage) {
       if ($storage_definition->uuid() != $this->original->getFieldStorageDefinition()->uuid()) {
         throw new FieldException("Cannot change an existing field's storage.");
       }
-      // Set the default field settings.
-      $this->settings += $field_type_manager->getDefaultFieldSettings($storage_definition->type);
       // Notify the entity storage.
       $entity_manager->getStorage($this->entity_type)->onFieldDefinitionUpdate($this, $this->original);
     }