It is possible to
multiple times (like when it is an button). Because the view does not appear directly this can be tapped multiple times causing strange behaviour.
Multiple login views will appear and the view controller structure will start containing errors. Also authorising and than cancelling a second one will cause the login to the cancelled.
This can be solved in the app of course but in my opinion this is a bug that should be handled in the framework that only one login attempt can be done at the same time.