Alex Pott
--- a/core/tests/Drupal/KernelTests/Core/Config/ConfigImporterTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Config/ConfigImporterTest.php
    $this->assertSame($collections, $event_collections);
  }

+  /**
+   * Tests the target storage caching during configuration import.
--- a/core/tests/Drupal/KernelTests/Core/Config/ConfigImporterTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Config/ConfigImporterTest.php
+   * Tests the target storage caching during configuration import.
+   */
+  public function testStorageComparerTargetStorage(): void {
+    $this->installConfig(['config_events_test']);
+    $this->copyConfig($this->container->get('config.storage'), $this->container->get('config.storage.sync'));
+    $this->assertTrue($this->container->get('module_installer')->uninstall(['config_test']));
+    \Drupal::state()->set('config_events_test.all_events', []);
+    \Drupal::state()->set('config_test_install.foo_value', 'transient');
+
+    // Prime the active config cache. If the ConfigImporter and StorageComparer
+    // do not manager the target storage correctly this cache can pollute the
+    // data.
+    \Drupal::configFactory()->get('config_test.system');
+
+    // Import the configuration. This results in a save event with the value
+    // changing from foo to bar.