is_authenticated returns True for logged out user

Question

I'm writing a server app using Django, Django REST framework, Django-rest-auth and Django-allauth. I have a method that's used to pass messages between users, and this should only happen when the receiver is logged in.

However, it seems that the user object's is_authenticated() method returns True even though the user has logged out (called rest-auth/logout/, which should in turn call Django's logout). What could cause this? Is there something I've missed here?

Here's the code I have:

class SendMessage(generics.CreateAPIView):
    permission_classes = (permissions.IsAuthenticated,)
    serializer_class = MessageSerializer

    def perform_create(self, serializer):
        m = self.request.data['msg']
        targetUser = User.objects.get(pk = self.request.data['user'])

        if targetUser.is_authenticated():
            # Send message
        else:
            # Don't send message

Answer 1

Unfortunately, the is_authenticated() method always returns true.

 def is_authenticated(self):
    """
    Always return True. This is a way to tell if the user has been
    authenticated in templates.
    """
    return True

It is meant to discern between a User instance and an AnonymousUser instance, which is what the User is set as when they do not pass authentication.