diff --git a/Eigen/src/Core/Map.h b/Eigen/src/Core/Map.h
index dd0673609..2bf80b3af 100644
--- a/Eigen/src/Core/Map.h
+++ b/Eigen/src/Core/Map.h
@@ -102,7 +102,7 @@ struct traits<Map<PlainObjectType, MapOptions, StrideType> >
                            || HasNoOuterStride
                            || ( OuterStrideAtCompileTime!=Dynamic
                            && ((static_cast<int>(sizeof(Scalar))*OuterStrideAtCompileTime)%16)==0 ) ),
-    Flags0 = TraitsBase::Flags,
+    Flags0 = TraitsBase::Flags & (~NestByRefBit),
     Flags1 = IsAligned ? (int(Flags0) | AlignedBit) : (int(Flags0) & ~AlignedBit),
     Flags2 = (bool(HasNoStride) || bool(PlainObjectType::IsVectorAtCompileTime))
            ? int(Flags1) : int(Flags1 & ~LinearAccessBit),
@@ -120,7 +120,6 @@ template<typename PlainObjectType, int MapOptions, typename StrideType> class Ma
   public:
 
     typedef MapBase<Map> Base;
-
     EIGEN_DENSE_PUBLIC_INTERFACE(Map)
 
     typedef typename Base::PointerType PointerType;
@@ -181,7 +180,6 @@ template<typename PlainObjectType, int MapOptions, typename StrideType> class Ma
       PlainObjectType::Base::_check_template_params();
     }
 
-
     EIGEN_INHERIT_ASSIGNMENT_OPERATORS(Map)
 
   protected: