diff --git a/addons/stock/models/stock_production_lot.py b/addons/stock/models/stock_production_lot.py
index 008aca62feb..e311ad3df6f 100644
--- a/addons/stock/models/stock_production_lot.py
+++ b/addons/stock/models/stock_production_lot.py
@@ -94,6 +94,7 @@ class ProductionLot(models.Model):
                 ))
         return super(ProductionLot, self).write(vals)
 
+    @api.depends('quant_ids', 'quant_ids.quantity')
     def _product_qty(self):
         for lot in self:
             # We only care for the quants in internal or transit locations.