Support case 00448719 was opened and the following was provided via the case:
The ‘Unlock Account’ functionality is not available from the ‘Modify My Endpoint Account’
task when using it in ‘My Profile’ screen of the Portal.
This means that a user cannot unlock his own account , users can unlock only other users’ accounts.
If you have to allow a user to unlock his own account you will have to use the
‘Modify User’s Endpoint Account’ task so the user will unlock his own account using
the Access module (Access -> Request for Self).