diff --git a/lib/Alchemy/Phrasea/Collection/Repository/ArrayCacheCollectionRepository.php b/lib/Alchemy/Phrasea/Collection/Repository/ArrayCacheCollectionRepository.php
index 2902841f6b..45df2e1f6f 100644
--- a/lib/Alchemy/Phrasea/Collection/Repository/ArrayCacheCollectionRepository.php
+++ b/lib/Alchemy/Phrasea/Collection/Repository/ArrayCacheCollectionRepository.php
@@ -54,7 +54,7 @@ class ArrayCacheCollectionRepository implements CollectionRepository
         $this->collectionRepository->save($collection);
 
         if ($this->collectionCache !== null) {
-            $this->collectionCache[$collection->get_coll_id()] = $collection;
+            $this->collectionCache = null;
         }
     }
 }