Oak Repository does not set property “jcr:createdBy” when saving a new “nt:file” node

[Emmanuel Kasper]

Hi all

I am saving documents inside oak (1.8.3) , with mongodb as the backend, 
and I noticed the jcr:createdBy property is not set as expected on new 
nodes,
although jcr:lastModified is set. I was expecting jcr:createdBy to be 
set with the user string I used to login.

Code similar to this is used to login:
String username = 'harry';
Credentials loginCredentials = new UserIdCredentials(username);

Repository oakRepo = new Jcr(new Oak(mongoBuilder)).createRepository;
Session session = oakRepo.login(loginCredentials);

I am then using the session object to create nodes, doing like

node = nodeParent.addNode(fileName, "nt:file");
session.getSession.save();

Am I missing something ?

Emmanuel