diff --git a/sf_manufacturing/models/mrp_production.py b/sf_manufacturing/models/mrp_production.py
index b4367212..011c5f7e 100644
--- a/sf_manufacturing/models/mrp_production.py
+++ b/sf_manufacturing/models/mrp_production.py
@@ -794,6 +794,7 @@ class MrpProduction(models.Model):
                                groupby(production_all, key=lambda x: x.product_id.id)}
         for product_id, pd in grouped_product_ids.items():
             product_id_to_production_names[product_id] = [p.name for p in pd]
+        sorted_workorders = None
         for production in production_all:
             proc_workorders = []
             process_parameter_workorder = self.env['mrp.workorder'].search(