diff --git a/include/proxnlp/modelling/spaces/pinocchio-groups.hpp b/include/proxnlp/modelling/spaces/pinocchio-groups.hpp
index 2f43e0d2..d8759b66 100644
--- a/include/proxnlp/modelling/spaces/pinocchio-groups.hpp
+++ b/include/proxnlp/modelling/spaces/pinocchio-groups.hpp
@@ -84,6 +84,8 @@ struct PinocchioLieGroup
 
   PointType rand() const { return lg_.random(); }
   bool isNormalized(const ConstVectorRef &x) const {
+    if (x.size() < nx())
+      return false;
     return lg_.isNormalized(x);
   }
 };