diff --git a/src/Core/Entity/ClonePropertiesTrait.php b/src/Core/Entity/ClonePropertiesTrait.php
index <HASH>..<HASH> 100644
--- a/src/Core/Entity/ClonePropertiesTrait.php
+++ b/src/Core/Entity/ClonePropertiesTrait.php
@@ -47,6 +47,8 @@ trait ClonePropertiesTrait
                     $collection->add(clone $item);
                 }
                 $value = $collection;
+            } elseif(null === $value) {
+
             } else {
                 $value = clone $value;
             }
[Core] fixes unitest.