Unexpected error occurs when adding a user with account that already exists on OpenDJ

See http://wiki.evolveum.com/display/midPoint/Test+Scenarios, consistency test #11:

Prerequisites:

• OpenDJ running
• account with dn: uid=a,ou=People,dc=example,dc=com existing there
• midPoint user nor account "a" existing

Steps:
(1) create user "a", setting name=fullname=familyname=a, assigning account on OpenDJ
(2) click on Save

Unexpected error occurs. Although consistency mechanism seems to apply, change executor fails with the message

ERROR: duplicate key value violates unique constraint "m_user_name_norm_key" Detail: Key (name_norm)=(a) already exists.
Param: object: user:null(a)
Cause:

ERROR: duplicate key value violates unique constraint "m_user_name_norm_key"
Detail: Key (name_norm)=(a) already exists.