[ConfirmRegister] Error if username has only digits #88

I'm trying to create registration with only email needed. I generate usernames like 4568245873 but when i try to confirm registration - i see 404 error page. I tried to create user using old registration - when i type username like "Skippidar" - everything is ok and i can verify my email, but if i type 0000000007 or any other digits - i see 404 error page again.

I solved it by adding "u" at the beginning when generating username. But i think that's MODX's registry bug, so it would be better to use not
$this->modx->registry->login->subscribe('/useractivation/'.$this->user->get('username'));
but
$this->modx->registry->login->subscribe('/useractivation/user'.$this->user->get('username'));