diff --git a/Classes/EventListener/PageIndexer/FrontendGroupsModifier.php b/Classes/EventListener/PageIndexer/FrontendGroupsModifier.php
index da9391d3ec..e4dd283a0e 100644
--- a/Classes/EventListener/PageIndexer/FrontendGroupsModifier.php
+++ b/Classes/EventListener/PageIndexer/FrontendGroupsModifier.php
@@ -19,6 +19,7 @@
 
 use ApacheSolrForTypo3\Solr\Access\Rootline;
 use ApacheSolrForTypo3\Solr\IndexQueue\FrontendHelper\AuthorizationService;
+use ApacheSolrForTypo3\Solr\IndexQueue\FrontendHelper\PageIndexer;
 use ApacheSolrForTypo3\Solr\IndexQueue\PageIndexerRequest;
 use ApacheSolrForTypo3\Solr\System\Logging\SolrLogManager;
 use TYPO3\CMS\Core\Http\JsonResponse;
@@ -29,6 +30,8 @@
 /**
  * Class FrontendGroupsModifier is responsible to fake the fe_groups to make
  * the indexing of access restricted pages and content elements.
+ *
+ * This class is involved only on {@link PageIndexer} processing.
  */
 class FrontendGroupsModifier
 {
@@ -40,7 +43,9 @@ class FrontendGroupsModifier
     public function __invoke(ModifyResolvedFrontendGroupsEvent $event): void
     {
         $pageIndexerRequest = $event->getRequest()->getAttribute('solr.pageIndexingInstructions');
-        if (!$pageIndexerRequest instanceof PageIndexerRequest) {
+        if (
+            !$pageIndexerRequest instanceof PageIndexerRequest
+            || !in_array(PageIndexer::ACTION_NAME, $pageIndexerRequest->getActions())) {
             return;
         }
 
diff --git a/Classes/IndexQueue/FrontendHelper/PageIndexer.php b/Classes/IndexQueue/FrontendHelper/PageIndexer.php
index be8578452e..8ff018aa09 100644
--- a/Classes/IndexQueue/FrontendHelper/PageIndexer.php
+++ b/Classes/IndexQueue/FrontendHelper/PageIndexer.php
@@ -59,12 +59,14 @@
  */
 class PageIndexer implements FrontendHelper, SingletonInterface
 {
+    public const ACTION_NAME = 'indexPage';
+
     protected bool $activated = false;
 
     /**
      * This frontend helper's executed action.
      */
-    protected string $action = 'indexPage';
+    protected string $action = self::ACTION_NAME;
 
     /**
      * Index Queue page indexer request.
diff --git a/Classes/IndexQueue/FrontendHelper/UserGroupDetector.php b/Classes/IndexQueue/FrontendHelper/UserGroupDetector.php
index 6869155da2..b095fb3b1e 100644
--- a/Classes/IndexQueue/FrontendHelper/UserGroupDetector.php
+++ b/Classes/IndexQueue/FrontendHelper/UserGroupDetector.php
@@ -34,6 +34,8 @@
  */
 class UserGroupDetector implements FrontendHelper, SingletonInterface
 {
+    public const ACTION_NAME = 'findUserGroups';
+
     /**
      * Index Queue page indexer request.
      */
@@ -42,7 +44,7 @@ class UserGroupDetector implements FrontendHelper, SingletonInterface
     /**
      * This frontend helper's executed action.
      */
-    protected string $action = 'findUserGroups';
+    protected string $action = self::ACTION_NAME;
 
     /**
      * Holds the original, unmodified TCA during user group detection
@@ -96,9 +98,8 @@ public function deactivateTcaFrontendGroupEnableFields(ModifyTypoScriptConfigEve
             return;
         }
         if (empty($this->originalTca)) {
-            return;
+            $this->originalTca = $GLOBALS['TCA'];
         }
-        $this->originalTca = $GLOBALS['TCA'];
 
         foreach ($GLOBALS['TCA'] as $tableName => $tableConfiguration) {
             if (isset($GLOBALS['TCA'][$tableName]['ctrl']['enablecolumns']['fe_group'])) {
@@ -117,8 +118,7 @@ public function deactivateTcaFrontendGroupEnableFields(ModifyTypoScriptConfigEve
     public function getPage_preProcess(BeforePageIsRetrievedEvent $event): void
     {
         if ($this->activated) {
-            //$event->skipGroupAccessCheck();
-            $disableGroupAccessCheck = true;
+            $event->skipGroupAccessCheck();
         }
     }
 
@@ -227,6 +227,7 @@ protected function getFrontendGroups(): array
     public function deactivate(PageIndexerResponse $response): void
     {
         $this->activated = false;
+        $GLOBALS['TCA'] = $this->originalTca;
         $response->addActionResult($this->action, $this->getFrontendGroups());
     }
 }
diff --git a/Configuration/Services.yaml b/Configuration/Services.yaml
index af7f93ee1e..9a9b8f2824 100644
--- a/Configuration/Services.yaml
+++ b/Configuration/Services.yaml
@@ -295,6 +295,10 @@ services:
       - name: event.listener
         identifier: 'solr.index.PageFieldMappingIndexer'
 
+  ApacheSolrForTypo3\Solr\IndexQueue\FrontendHelper\UserGroupDetector:
+    autowire: true
+    autoconfigure: true
+
   ApacheSolrForTypo3\Solr\EventListener\Extbase\PersistenceEventListener:
     autowire: true
     tags:
diff --git a/Tests/Integration/IndexQueue/PageIndexerTest.php b/Tests/Integration/IndexQueue/PageIndexerTest.php
index 2905556b18..bde52e85d9 100644
--- a/Tests/Integration/IndexQueue/PageIndexerTest.php
+++ b/Tests/Integration/IndexQueue/PageIndexerTest.php
@@ -24,6 +24,8 @@
 use PHPUnit\Framework\Attributes\DataProvider;
 use PHPUnit\Framework\Attributes\Test;
 use Traversable;
+use TYPO3\CMS\Core\Cache\CacheManager;
+use TYPO3\CMS\Core\Cache\Frontend\VariableFrontend;
 use TYPO3\CMS\Core\Utility\GeneralUtility;
 use TYPO3\TestingFramework\Core\Functional\Framework\Frontend\InternalRequest;
 
@@ -50,14 +52,14 @@ protected function setUp(): void
             page.10.stdWrap.dataWrap = <!--TYPO3SEARCH_begin-->|<!--TYPO3SEARCH_end-->
             '
         );
+        $this->cleanUpAllCoresOnSolrServerAndAssertEmpty();
     }
 
     /**
-     * Executed after each test. Emptys solr and checks if the index is empty
+     * Executed after each test. Empties solr and checks if the index is empty
      */
     protected function tearDown(): void
     {
-        $this->cleanUpAllCoresOnSolrServerAndAssertEmpty();
         parent::tearDown();
     }
 
@@ -73,9 +75,6 @@ public function canIndexPageWithAccessProtectedContentIntoSolr(
         int $expectedNumFoundLoggedInUser,
         string $core = 'core_en'
     ): void {
-        self::markTestSkipped('@todo: Fix it. See: https://github.com/TYPO3-Solr/ext-solr/issues/4161');
-
-        $this->cleanUpAllCoresOnSolrServerAndAssertEmpty();
         $this->importCSVDataSet(__DIR__ . '/Fixtures/' . $fixture . '.csv');
 
         $createPageIndexerMock = function(): PageIndexerRequest {
@@ -279,6 +278,9 @@ protected function sendPageIndexerRequest(string $url, PageIndexerRequest $reque
             $indexerResponse->addActionResult($action, $actionResult);
         }
 
+        /** @var VariableFrontend $runtimeCache */
+        $runtimeCache = GeneralUtility::makeInstance(CacheManager::class)->getCache('runtime');
+        $runtimeCache->flush();
         return $indexerResponse;
     }
 }
diff --git a/Tests/Integration/IntegrationTestBase.php b/Tests/Integration/IntegrationTestBase.php
index 89a7ff6e70..0b31fed4cf 100644
--- a/Tests/Integration/IntegrationTestBase.php
+++ b/Tests/Integration/IntegrationTestBase.php
@@ -24,6 +24,8 @@
 use ReflectionClass;
 use ReflectionException;
 use ReflectionObject;
+use TYPO3\CMS\Core\Cache\CacheManager;
+use TYPO3\CMS\Core\Cache\Frontend\VariableFrontend;
 use TYPO3\CMS\Core\Core\Environment;
 use TYPO3\CMS\Core\Database\ConnectionPool;
 use TYPO3\CMS\Core\Exception\SiteNotFoundException;
@@ -461,6 +463,10 @@ protected function executePageIndexer(string $url, Item $item, int $frontendUser
             $requestContext = (new InternalRequestContext())->withFrontendUserId($frontendUserId);
         }
         $response = $this->executeFrontendSubRequest($request, $requestContext);
+        /** @var VariableFrontend $runtimeCache */
+        $runtimeCache = GeneralUtility::makeInstance(CacheManager::class)->getCache('runtime');
+        $runtimeCache->flush();
+
         $response->getBody()->rewind();
         return $response;
     }