Hold off on doing anything. It appears to be fixed in our next ER2 release (Based on my building locally and testing).
There is nothing we can do for getting rid of the blank page. When a user without any of the webapp roles tries to login, EAP responds that way. The auth request is not even handed over to the webapp in such case. This is an IT issue. If users are created properly, with the right roles, they will never see a blank screen, as it does not make sense to register a user not having a valid role.