NPE exception when logging out from a simple page on which some new ACLs had been defined

Created an empty new site with the last build 25745, created a new simple page with root account and then on which added some new ACL (steven as RW and John RWA) . then clicked on logging out link of the template (form this new created page) , see the attachment for the exception I had in the console
I'm Not sure it's related to ACL modification but wanted to give you my detailed test scenario.