diff --git a/addons/sale/models/sale_order.py b/addons/sale/models/sale_order.py
index b53d39684cb..d5140973548 100644
--- a/addons/sale/models/sale_order.py
+++ b/addons/sale/models/sale_order.py
@@ -919,7 +919,8 @@ class SaleOrder(models.Model):
         context.pop('default_name', None)
 
         self.with_context(context)._action_confirm()
-        if self.create_uid.has_group('sale.group_auto_done_setting'):  # Public user can confirm SO
+        if self[:1].create_uid.has_group('sale.group_auto_done_setting'):
+            # Public user can confirm SO, so we check the group on any record creator.
             self.action_lock()
 
         return True