diff --git a/Classes/Content/ContentTypeManager.php b/Classes/Content/ContentTypeManager.php
index 3d8292c0f..be47be83a 100644
--- a/Classes/Content/ContentTypeManager.php
+++ b/Classes/Content/ContentTypeManager.php
@@ -56,7 +56,7 @@ public function fetchContentTypes(): iterable
                     (array) FluidFileBasedContentTypeDefinition::fetchContentTypes(),
                     (array) RecordBasedContentTypeDefinition::fetchContentTypes()
                 );
-                $this->typeNames = array_keys($types);
+                $this->typeNames = array_merge($this->typeNames, array_keys($types));
             } catch (DBALException $error) {
                 // Suppress schema- or connection-related issues
             } catch (NoSuchCacheException $error) {