Original Drupal issue with a patch that appears to be working well though I haven't ported the patch yet. By Rich Burke (richburke), chrisgross, Cleber Gasparoto (chgasparoto), Vitor Machado (vmachado), and Brian Osborne (bkosborne).
When a user that's been authenticated through SSO tries to create other users, those users have the name & email address of the admin applied to them. This results in a DB constraint error on the user name.
Original Drupal issue with a patch that appears to be working well though I haven't ported the patch yet. By Rich Burke (richburke), chrisgross, Cleber Gasparoto (chgasparoto), Vitor Machado (vmachado), and Brian Osborne (bkosborne).
drupal7-simplesamlphp_auth-admin-users-cannot-other-users-9291915-11-with-early-return.patch.txt