Prevent multiples sub-queries.

src/Bundle/ChillMainBundle/Doctrine/ORM/Hydration/FlatHierarchyEntityHydrator.php

@@ -15,7 +15,13 @@ final class FlatHierarchyEntityHydrator extends ObjectHydrator
     {
         $generator = $this->buildRecursively(
             parent::hydrateAllData(),
-            static fn($value): iterable => $value->getChildren(),
+            static function($value): iterable {
+                $children = $value->getChildren();
+
+                $children->setInitialized(true);
+
+                return $children;
+            }
         );
 
         $result = [];