I tried to edit https://phabricator.wikimedia.org/project/profile/1587/ Google-Code-In-2015 to add @Nemo_bis as an admin and on save got:
Unhandled Exception ("PhabricatorDataNotAttachedException") Attempting to access attached data on PhabricatorProject, but the data is not actually attached. Before accessing attachable data on an object, you must load and attach it. Data is normally attached by calling the corresponding needX() method on the Query class when the object is loaded. You can also call the corresponding attachX() method explicitly.
I was able to add @Aklapper to the project description; only @Nemo_bis causes the error