I think this is the issue I was talking about with the factory earlier. By default, the injector just calls the default constructor when creating a new instance, as it doesn't know how to do anything else. It never knows to call your `get_inst` method where you do the `$_COOKIE` set up stuff, so that never gets done for the new instance. This is why I think a factory would be useful.

http://doc.silverstripe.org/framework/en/reference/injector#factories