create 2 user

1. admin1 admin1@test.de
2. admin2 admin2@test.de

than

edit amdin2 and change email to admin1@test.de
=> publish
=> ez will notify you that the email already exists
=> ok => discard draft

....
than go to admin2 user again and you will see that the user
has the email of admin1@test.de

=> but we discarded the draft
=> ez has stored the wrong value but should not