diff --git a/tiramisu/option/option.py b/tiramisu/option/option.py
index 0b45b22..fce60f3 100644
--- a/tiramisu/option/option.py
+++ b/tiramisu/option/option.py
@@ -468,7 +468,7 @@ class Option(OnlyOption):
             if option_bag.config_bag is undefined:
                 cconfig_bag = undefined
             else:
-                cconfig_bag = option_bag.config_bag
+                cconfig_bag = option_bag.config_bag.copy()
                 cconfig_bag.set_permissive()
             for cons_id, func, all_cons_opts, params in consistencies:
                 warnings_only = params.get('warnings_only', False)