diff --git a/typo3/sysext/core/Classes/DataHandling/SlugHelper.php b/typo3/sysext/core/Classes/DataHandling/SlugHelper.php
index 77aee4f2a7f26d87487783ee23885d92641e6126..d6327ebbc7ad290474b5dcaff99438d671fe8c89 100644
--- a/typo3/sysext/core/Classes/DataHandling/SlugHelper.php
+++ b/typo3/sysext/core/Classes/DataHandling/SlugHelper.php
@@ -303,6 +303,9 @@ class SlugHelper
             $siteOfCurrentRecord = $siteFinder->getSiteByPageId($pageId);
         } catch (SiteNotFoundException $e) {
             // Not within a site, so nothing to do
+            // TODO: Rather than silently ignoring this misconfiguration,
+            // a warning should be thrown here, or maybe even let the
+            // exception bubble up and catch it in places that uses this API
             return true;
         }
         foreach ($records as $record) {
diff --git a/typo3/sysext/core/Classes/Routing/Aspect/SiteAccessorTrait.php b/typo3/sysext/core/Classes/Routing/Aspect/SiteAccessorTrait.php
index cb444d519fb934d5d322a10d923984c97f07a4bd..1fce0616a8a5597c7e27f254ce60fd25b0a72629 100644
--- a/typo3/sysext/core/Classes/Routing/Aspect/SiteAccessorTrait.php
+++ b/typo3/sysext/core/Classes/Routing/Aspect/SiteAccessorTrait.php
@@ -95,7 +95,11 @@ trait SiteAccessorTrait
             $expectedSite = $this->getSiteMatcher()->matchByPageId($pageId);
             return $expectedSite->getRootPageId() === $this->site->getRootPageId();
         } catch (SiteNotFoundException $exception) {
-            return false;
+            // Same as in \TYPO3\CMS\Core\DataHandling\SlugHelper::isUniqueInSite
+            // where it is assumed that a record, that is not in site context,
+            // but still configured uniqueInSite is unique. We therefore must assume
+            // the resolved record to be rightfully part of the current site.
+            return true;
         }
     }