diff --git a/core/lib/Drupal/Core/Config/TypedConfigManager.php b/core/lib/Drupal/Core/Config/TypedConfigManager.php
index 5c7aeeb..6ccf8fd 100644
--- a/core/lib/Drupal/Core/Config/TypedConfigManager.php
+++ b/core/lib/Drupal/Core/Config/TypedConfigManager.php
@@ -107,9 +107,13 @@ public function buildDataDefinition(array $definition, $value, $name = NULL, $pa
       // Remove the type from the definition so that it is replaced with the
       // concrete type from schema definitions.
       unset($definition['type']);
+
+      $definition += $this->getDefinition($type, TRUE, $replace);
+    }
+    else {
+      // Add default values from type definition.
+      $definition += $this->getDefinition($type);
     }
-    // Add default values from type definition.
-    $definition += $this->getDefinition($type);
 
     $data_definition = $this->createDataDefinition($definition['type']);
 
@@ -125,7 +129,7 @@ public function buildDataDefinition(array $definition, $value, $name = NULL, $pa
   /**
    * {@inheritdoc}
    */
-  public function getDefinition($base_plugin_id, $exception_on_invalid = TRUE) {
+  public function getDefinition($base_plugin_id, $exception_on_invalid = TRUE, $value = NULL) {
     $definitions = $this->getDefinitions();
     if (isset($definitions[$base_plugin_id])) {
       $type = $base_plugin_id;
@@ -145,6 +149,14 @@ public function getDefinition($base_plugin_id, $exception_on_invalid = TRUE) {
       // Preserve integer keys on merge, so sequence item types can override
       // parent settings as opposed to adding unused second, third, etc. items.
       $definition = NestedArray::mergeDeepArray(array($merge, $definition), TRUE);
+
+      // If the sub type has a bracket then lets look that up as well.
+      if (isset($value) && strpos($definition['type'], ']')) {
+        $sub_type = $this->replaceName($definition['type'], $value);
+        $merge = $definitions[$sub_type];
+        $definition = NestedArray::mergeDeepArray(array($merge, $definition), TRUE);
+      }
+
       // Unset type so we try the merge only once per type.
       unset($definition['type']);
       $this->definitions[$type] = $definition;
diff --git a/core/modules/config/src/Tests/ConfigSchemaTest.php b/core/modules/config/src/Tests/ConfigSchemaTest.php
index a94e26a..ee58b0d 100644
--- a/core/modules/config/src/Tests/ConfigSchemaTest.php
+++ b/core/modules/config/src/Tests/ConfigSchemaTest.php
@@ -498,4 +498,37 @@ public function testConfigSchemaInfoAlter() {
     $this->assertEqual($definitions['config_schema_test.hook']['additional_metadata'], 'new schema info');
   }
 
+  /**
+   * Tests saving config when the type is wrapped by a dynamic type.
+   */
+  public function testConfigSaveWithWrappingSchema() {
+    $untyped_values = [
+      'tests' => [
+        [
+          'wrapper_value' => 'foo',
+          'plugin_id' => 'wrapper',
+          'internal_value' => 100,
+        ],
+      ],
+    ];
+    $untyped_to_typed = $untyped_values;
+
+    $typed_values = array(
+      'tests' => [
+        [
+          'wrapper_value' => 'foo',
+          'plugin_id' => 'wrapper',
+          'internal_value' => '100',
+        ],
+      ],
+    );
+
+    // Save config which has a schema that enforces types.
+    \Drupal::configFactory()->getEditable('wrapping.config_schema_test.plugin_types')
+      ->setData($untyped_to_typed)
+      ->save();
+    $this->assertIdentical(\Drupal::config('wrapping.config_schema_test.plugin_types')
+      ->get(), $typed_values);
+  }
+
 }
diff --git a/core/modules/config/tests/config_schema_test/config/schema/config_schema_test.schema.yml b/core/modules/config/tests/config_schema_test/config/schema/config_schema_test.schema.yml
index 004ae2b..c716537 100644
--- a/core/modules/config/tests/config_schema_test/config/schema/config_schema_test.schema.yml
+++ b/core/modules/config/tests/config_schema_test/config/schema/config_schema_test.schema.yml
@@ -213,3 +213,23 @@ config_test.dynamic.*.third_party.config_schema_test:
       type: integer
     string:
       type: string
+
+wrapping.config_schema_test.plugin_types:
+  type: config_object
+  mapping:
+    tests:
+      type: sequence
+      sequence:
+        - type: wrapping.test.plugin_types.[plugin_id]
+
+wrapping.test.plugin_types.*:
+  type: test.plugin_types.[plugin_id]
+  mapping:
+    wrapper_value:
+      type: string
+
+test.plugin_types.wrapper:
+  type: test.plugin_types
+  mapping:
+    internal_value:
+      type: string