diff --git a/addons/mrp/models/mrp_production.py b/addons/mrp/models/mrp_production.py
index 45eb460a25b..0adfcea608a 100644
--- a/addons/mrp/models/mrp_production.py
+++ b/addons/mrp/models/mrp_production.py
@@ -455,7 +455,7 @@ class MrpProduction(models.Model):
                 move[0].with_context(do_not_unreserve=True).write({'product_uom_qty': quantity})
                 move[0]._recompute_state()
                 move[0]._action_assign()
-                move.unit_factor = quantity / move.raw_material_production_id.product_qty
+                move[0].unit_factor = quantity / move[0].raw_material_production_id.product_qty
             elif quantity < 0:  # Do not remove 0 lines
                 if move[0].quantity_done > 0:
                     raise UserError(_('Lines need to be deleted, but can not as you still have some quantities to consume in them. '))