A user account is created and authenticated correctly, but the user cannot sign in from the login page because the new account does not have the password saved at all. The corresponding password field in the user table in the db is empty. $wgPasswordSalt is not set.
Topic on Extension talk:Ticket Authentication/Flow
Looks like Ticket Authentication tries to update the db directly using User->saveSettings, however v1.27 no longer allows the password to be saved this way (actively looks for a removes the password field from account creation params).