Configured a service in the services.php with the id: 'testbundle.test_this'
Using it works perfect, except one strange behavior.

Calling it in your front controller with:
$this->get('testbundle.testthis');
Will throw no error, and gives you a NEW copy on the class, and replaces it in its container.
Calling $this->get('testbundle.test_this') afterwards will give you the NEW object.

Expected behavior: a error thrown of unknown id.