diff --git a/core/lib/Drupal/Core/Session/SessionManager.php b/core/lib/Drupal/Core/Session/SessionManager.php
index 52b3542..3c71930 100644
--- a/core/lib/Drupal/Core/Session/SessionManager.php
+++ b/core/lib/Drupal/Core/Session/SessionManager.php
@@ -174,6 +174,7 @@ protected function startNow() {
     // Restore session data.
     if ($this->startedLazy) {
       $_SESSION = $session_data;
+      $this->loadSession();
     }
 
     return $result;
diff --git a/core/modules/system/src/Tests/Session/SessionTest.php b/core/modules/system/src/Tests/Session/SessionTest.php
index 75b194a..3f26ee9 100644
--- a/core/modules/system/src/Tests/Session/SessionTest.php
+++ b/core/modules/system/src/Tests/Session/SessionTest.php
@@ -100,6 +100,10 @@ function testDataPersistence() {
     $this->drupalGet('session-test/get');
     $this->assertText($value_1, 'Session data is not saved for drupal_save_session(FALSE).', 'Session');
 
+    // Test property added to session object form hook_user_login().
+    $this->drupalGet('session-test/get-from-session-object');
+    $this->assertText('foobar', 'Session data is saved in Session() object.', 'Session');
+
     // Switch browser cookie to anonymous user, then back to user 1.
     $this->sessionReset();
     $this->sessionReset($user->id());
diff --git a/core/modules/system/tests/modules/session_test/session_test.module b/core/modules/system/tests/modules/session_test/session_test.module
index 0fb2ae4..6a08211 100644
--- a/core/modules/system/tests/modules/session_test/session_test.module
+++ b/core/modules/system/tests/modules/session_test/session_test.module
@@ -9,4 +9,6 @@ function session_test_user_login($account) {
     // before hook_user_login() was called.
     exit;
   }
+  // Add some data in the session for retrieval testing purpose.
+  \Drupal::request()->getSession()->set("session_test_key", "foobar");
 }
diff --git a/core/modules/system/tests/modules/session_test/session_test.routing.yml b/core/modules/system/tests/modules/session_test/session_test.routing.yml
index 8b9393e..fce0fc9 100644
--- a/core/modules/system/tests/modules/session_test/session_test.routing.yml
+++ b/core/modules/system/tests/modules/session_test/session_test.routing.yml
@@ -5,7 +5,13 @@ session_test.get:
     _controller: '\Drupal\session_test\Controller\SessionTestController::get'
   requirements:
     _access: 'TRUE'
-
+session_test.get_from_session_object:
+  path: '/session-test/get-from-session-object'
+  defaults:
+    _title: 'Session value'
+    _controller: '\Drupal\session_test\Controller\SessionTestController::getFromSessionObject'
+  requirements:
+    _access: 'TRUE'
 session_test.id:
   path: '/session-test/id'
   defaults:
diff --git a/core/modules/system/tests/modules/session_test/src/Controller/SessionTestController.php b/core/modules/system/tests/modules/session_test/src/Controller/SessionTestController.php
index 1ae9a79..2db6f21 100644
--- a/core/modules/system/tests/modules/session_test/src/Controller/SessionTestController.php
+++ b/core/modules/system/tests/modules/session_test/src/Controller/SessionTestController.php
@@ -31,6 +31,19 @@ public function get() {
   }
 
   /**
+   * Prints the stored session value to the screen.
+   *
+   * @return string
+   *   A notification message.
+   */
+  public function getFromSessionObject() {
+    $value = \Drupal::request()->getSession()->get("session_test_key");
+    return empty($value)
+    ? []
+    : ['#markup' => $this->t('The current value of the stored session variable is: %val', array('%val' => $value))];
+  }
+
+  /**
    * Print the current session ID.
    *
    * @return string