diff --git a/core/lib/Drupal/Core/Session/AccountProxy.php b/core/lib/Drupal/Core/Session/AccountProxy.php
index cb6fbd2..4a9dd05 100644
--- a/core/lib/Drupal/Core/Session/AccountProxy.php
+++ b/core/lib/Drupal/Core/Session/AccountProxy.php
@@ -111,7 +111,9 @@ public function getAccount() {
   public function impersonateAccount(AccountInterface $account) {
     // Prevent session information from being saved and push the previous account.
     array_push($this->accountStack, $this->account);
-    $this->originalSessionSaving = $this->sessionManager->isEnabled();
+    if (!isset($this->originalSessionSaving)) {
+      $this->originalSessionSaving = $this->sessionManager->isEnabled();
+    }
     $this->sessionManager->disable();
     $this->setAccount($account);
     return $this;
diff --git a/core/lib/Drupal/Core/Session/AccountProxyInterface.php b/core/lib/Drupal/Core/Session/AccountProxyInterface.php
index 3c3f072..b88ba0b 100644
--- a/core/lib/Drupal/Core/Session/AccountProxyInterface.php
+++ b/core/lib/Drupal/Core/Session/AccountProxyInterface.php
@@ -49,6 +49,9 @@ public function impersonateAccount(AccountInterface $account);
    *
    * @return \Drupal\Core\Session\AccountInterface
    *   $this.
+   *
+   * @throws \RuntimeException
+   *   When there are no more account impersonations to revert.
    */
   public function revertAccount();
 
@@ -60,6 +63,9 @@ public function revertAccount();
    *
    * @return \Drupal\Core\Session\AccountInterface
    *   $this.
+   *
+   * @throws \RuntimeException
+   *   When there are no more account impersonations to revert.
    */
   public function revertAll();
 }