diff --git a/ext/custom-addons/dp_custom/models/sale.py b/ext/custom-addons/dp_custom/models/sale.py
index 4b9660e8..f2d96ab5 100644
--- a/ext/custom-addons/dp_custom/models/sale.py
+++ b/ext/custom-addons/dp_custom/models/sale.py
@@ -521,6 +521,10 @@ class SaleOrderLine(models.Model):
                                      precision_digits=precision_digits) != 0:
                         allowed_write = False
                         break
+                elif val_key in list(vals.keys()) and type(self.__getattribute__(val_key)) is type(self.env['product.uom']):
+                    if self.__getattribute__(val_key).id != vals[val_key]:
+                        allowed_write = False
+                        break
                 elif val_key in list(vals.keys()):
                     allowed_write = False
                     break