When I test manually, everything works, but RegisterCept.php functional test just won't pass

$I = new FunctionalTester($scenario);
$I->am('guest');
$I->wantTo('register');

$I->amOnPage('/');
$I->click('Register');
$I->seeCurrentUrlEquals('/register');

$I->fillField('username', 'John');
$I->fillField('email', 'john@example.com');
$I->fillField('password', 'password');
$I->fillField('password_confirmation', 'password');
$I->click('Register');

$I->seeCurrentUrlEquals(''); // fails but /register passes
$I->see('Account created successfully. Validate your email before signing in.'); // also fails

It should redirect to site.dev/, but apparently it doesn't. Output file shows normal /register page HTML without any messages/errors. Trying to force an error (The Password field is required for example) also fails $I->see(). Removing the mail send also doesn't work. DB record doesn't get created... I've tried everything I can think of and nothing seems to work. Even creating a simple controller won't work

User::create(Input::all());
return Redirect::home()->withMessage('FooBar');

LoginCept and ActivateAccountCept work just fine.

Codeception version is 2.0.5