diff -u b/core/lib/Drupal/Core/TypedData/Plugin/DataType/Map.php b/core/lib/Drupal/Core/TypedData/Plugin/DataType/Map.php
--- b/core/lib/Drupal/Core/TypedData/Plugin/DataType/Map.php
+++ b/core/lib/Drupal/Core/TypedData/Plugin/DataType/Map.php
@@ -3,6 +3,7 @@
 namespace Drupal\Core\TypedData\Plugin\DataType;
 
 use Drupal\Core\TypedData\DataDefinition;
+use Drupal\Core\TypedData\MapDataDefinition;
 use Drupal\Core\TypedData\TypedData;
 use Drupal\Core\TypedData\ComplexDataInterface;
 
@@ -170,14 +171,23 @@
       $values = $this->values;
       if (is_array($values)) {
         foreach ($values as $key => $value) {
-          $properties[$key] = \Drupal::typedDataManager()->create(
+          if (!empty($value) && is_array($value)) {
+            $properties[$key] = \Drupal::typedDataManager()->create(
+              MapDataDefinition::create(),
+              $value,
+              $key
+            );
+          }
+          else {
+            $properties[$key] = \Drupal::typedDataManager()->create(
             // Give array's value a DataType,So that drupal can find which normalizer to be used to normalize it
             // Because we don't know the type of the value,so we use 'any',
             // If you don't want to use 'any',Please define it by yourself use setPropertyDefinition
-            DataDefinition::create('any'),
-            $value,
-            $key
-          );
+              DataDefinition::create('any'),
+              $value,
+              $key
+            );
+          }
         };
       }
     }