diff --git a/production.py b/production.py
index 293d96408b..aa23863f0c 100644
--- a/production.py
+++ b/production.py
@@ -651,6 +651,9 @@ class Production(ShipmentAssignMixin, Workflow, ModelSQL, ModelView):
         else:
             default = default.copy()
         default.setdefault('number', None)
+        default.setdefault('assigned_by')
+        default.setdefault('run_by')
+        default.setdefault('done_by')
         return super(Production, cls).copy(productions, default=default)
 
     def _get_move_planned_date(self):