diff --git a/core/lib/Drupal/Core/Config/TypedConfigManager.php b/core/lib/Drupal/Core/Config/TypedConfigManager.php
index 155246d..1181953 100644
--- a/core/lib/Drupal/Core/Config/TypedConfigManager.php
+++ b/core/lib/Drupal/Core/Config/TypedConfigManager.php
@@ -170,10 +170,11 @@ protected function getDefinitionWithReplacements($base_plugin_id, array $replace
 
       // Replace dynamic portions of the definition type.
       if (!empty($replacements) && strpos($definition['type'], ']')) {
-        $type = $this->determineType($this->replaceName($definition['type'], $replacements), $definitions);
+        $sub_type = $this->determineType($this->replaceName($definition['type'], $replacements), $definitions);
         // Merge the newly determined subtype definition with the original
         // definition.
-        $definition = NestedArray::mergeDeepArray([$definitions[$type], $definition], TRUE);
+        $definition = NestedArray::mergeDeepArray([$definitions[$sub_type], $definition], TRUE);
+        $type = "$type||$sub_type";
       }
       // Unset type so we try the merge only once per type.
       unset($definition['type']);
diff --git a/core/modules/config/src/Tests/ConfigSchemaTest.php b/core/modules/config/src/Tests/ConfigSchemaTest.php
index 56fe862..a89db0e 100644
--- a/core/modules/config/src/Tests/ConfigSchemaTest.php
+++ b/core/modules/config/src/Tests/ConfigSchemaTest.php
@@ -573,6 +573,10 @@ public function testConfigSaveWithWrappingSchemaDoubleBrackets() {
     $this->assertIdentical(\Drupal::config('wrapping.config_schema_test.double_brackets')
       ->get(), $typed_values);
 
+    $tests = \Drupal::service('config.typed')->get('wrapping.config_schema_test.double_brackets')->get('tests')->getElements();
+    $definition = $tests[0]->getDataDefinition()->toArray();
+    $this->assertEqual($definition['type'], 'wrapping.test.double_brackets.*||test.double_brackets.turtle.horse');
+
     $untyped_values = [
       'tests' => [
         [
@@ -602,6 +606,36 @@ public function testConfigSaveWithWrappingSchemaDoubleBrackets() {
       ->save();
     $this->assertIdentical(\Drupal::config('wrapping.config_schema_test.double_brackets')
       ->get(), $typed_values);
+
+    $tests = \Drupal::service('config.typed')->get('wrapping.config_schema_test.double_brackets')->get('tests')->getElements();
+    $definition = $tests[0]->getDataDefinition()->toArray();
+    $this->assertEqual($definition['type'], 'wrapping.test.double_brackets.*||test.double_brackets.cat.dog');
+
+    // Combine everything in a single save.
+    $typed_values = [
+      'tests' => [
+        [
+          'wrapper_value' => 'foo',
+          'foo' => 'cat',
+          'bar' => 'dog',
+          'another_key' => 100,
+        ],
+        [
+          'wrapper_value' => 'foo',
+          'foo' => 'turtle',
+          'bar' => 'horse',
+          'another_key' => '100',
+        ],
+      ],
+    ];
+    \Drupal::configFactory()->getEditable('wrapping.config_schema_test.double_brackets')
+      ->setData($typed_values)
+      ->save();
+    $tests = \Drupal::service('config.typed')->get('wrapping.config_schema_test.double_brackets')->get('tests')->getElements();
+    $definition = $tests[0]->getDataDefinition()->toArray();
+    $this->assertEqual($definition['type'], 'wrapping.test.double_brackets.*||test.double_brackets.cat.dog');
+    $definition = $tests[1]->getDataDefinition()->toArray();
+    $this->assertEqual($definition['type'], 'wrapping.test.double_brackets.*||test.double_brackets.turtle.horse');
   }
 
 }