diff --git a/modules/sale_promotion/sale.py b/modules/sale_promotion/sale.py
index 9fe0fc2e2e..530eb7378c 100644
--- a/modules/sale_promotion/sale.py
+++ b/modules/sale_promotion/sale.py
@@ -241,6 +241,8 @@ class Promotion(
         if self.unit:
             quantity = 0
             for line in sale.lines:
+                if line.type != 'line':
+                    continue
                 if self.is_valid_sale_line(line):
                     quantity += Uom.compute_qty(line.unit, line.quantity,
                         self.unit)