Are user accounts being created based on the E-mail ID and are these suddenly case sensitive? I am suddenly getting duplicate users being created (who have existing accounts in the system).
This is going to become a nightmare to manage if this is the case!
Further investigation into this would suggest that it is based on the username rather than the E-mail.
I have changed the case of an E-mail Address and a new account was created. The difference was that the username for the original account was different.
Again BIG problem, probably bigger that the case sensitivity because I now have to manually change a large number of usernames!