This is quite similar to the problem described in EZP-19473 and, basically, the eMail sent to the customer after a registration won't have any information with the username and the eMail, and the link to the user information will be invalid.

Steps to Reproduce

1. In the frontend, register a new eMail
2. Go to your mailbox and check the received eMail, it will look somewhat like:

A new user has registered.

Account information.
Username:
Email:

Link to user information:
http://your-site.com/content/view/full