diff --git a/tiramisu/option/masterslave.py b/tiramisu/option/masterslave.py
index 847d644..b0f6b46 100644
--- a/tiramisu/option/masterslave.py
+++ b/tiramisu/option/masterslave.py
@@ -229,7 +229,7 @@ class MasterSlaves(object):
                 else:
                     return value
             elif index is None:
-                multi.append(value, setitem=False, force=True, validate=validate,
+                multi.append(value, setitem=False, force=True, validate=False,
                              force_permissive=force_permissive)
             else:
                 multi = value
diff --git a/tiramisu/value.py b/tiramisu/value.py
index 8406071..f8b516d 100644
--- a/tiramisu/value.py
+++ b/tiramisu/value.py
@@ -770,8 +770,7 @@ class Multi(list):
         if 'validator' in setting_properties and validate:
             session = context.cfgimpl_get_values()._p_.getsession()
             fake_context = context._gen_fake_values(session)
-            fake_multi = fake_context.cfgimpl_get_values()._get_cached_value(
-                self.opt, path=self.path, validate=False)
+            fake_multi = Multi(list(self), weakref.ref(fake_context), self.opt, self.path)
             fake_multi._setitem(index, value, validate=False)
             self._validate(value, fake_context, index, True)
         #assume not checking mandatory property