diff --git a/core/lib/Drupal/Core/Plugin/DefaultPluginBag.php b/core/lib/Drupal/Core/Plugin/DefaultPluginBag.php
index 9287d7c..b488250 100644
--- a/core/lib/Drupal/Core/Plugin/DefaultPluginBag.php
+++ b/core/lib/Drupal/Core/Plugin/DefaultPluginBag.php
@@ -131,6 +131,15 @@ public function getConfiguration() {
    * {@inheritdoc}
    */
   public function setConfiguration($configuration) {
+    $this->configurations = array();
+    $this->pluginInstances = array();
+    $this->instanceIDs = array();
+
+    $instance_ids = array_keys($configuration);
+    $this->instanceIDs = array_combine($instance_ids, $instance_ids);
+    // Store the original order of the instance IDs for export.
+    $this->originalOrder = $this->instanceIDs;
+
     foreach ($configuration as $instance_id => $instance_configuration) {
       $this->setInstanceConfiguration($instance_id, $instance_configuration);
     }
diff --git a/core/modules/image/src/Tests/ImageImportTest.php b/core/modules/image/src/Tests/ImageImportTest.php
new file mode 100644
index 0000000..cf68007
--- /dev/null
+++ b/core/modules/image/src/Tests/ImageImportTest.php
@@ -0,0 +1,48 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\image\Tests\ImageImportTest.
+ */
+
+namespace Drupal\image\Tests;
+
+use Drupal\image\Entity\ImageStyle;
+use Drupal\simpletest\KernelTestBase;
+
+/**
+ * Tests config import for Image styles.
+ *
+ * @group image
+ */
+class ImageImportTest extends KernelTestBase {
+
+  public static $modules = array('image', 'image_module_test');
+
+  public function testImport() {
+    /**
+     * @var ImageStyle $style
+     */
+    $style = ImageStyle::create(array(
+      'name' => 'test'
+    ));
+
+    $style->addImageEffect(array('id' => 'image_module_test_null'));
+    $style->addImageEffect(array('id' => 'image_module_test_null'));
+    $style->save();
+
+    $this->assertEqual(count($style->getEffects()), 2, 'The entity contains two image effects.');
+
+    $uuid = \Drupal::service('uuid')->generate();
+    $style->set('effects', array(
+      $uuid => array(
+        'id' => 'image_module_test_null'
+      ),
+    ));
+    $style->save();
+
+    $style = ImageStyle::load('test');
+    $this->assertEqual(count($style->getEffects()), 1, 'The entity contains one image effects.');
+  }
+
+}