I'm working on odoo v.8, leave management module (Human resources). i have created employees and assigned 'user' profiles. Everything looks good and works fine most of the time (users able to login and access info as per permissions assigned).

However sometimes, i notice that some of the user names get 'auto' changed to 'administrator'. I need to go in and manually assign it back to the original user name. interestingly, even when the username gets changed to 'administrator' none of the permissions of admin are seen assigned and the user is logging into his account with his username and password only to find empty menu records. I'm not able to track a pattern for this. sometimes for testing, i submit/approve leaves of employees using the admin account.

Any suggestions on what setting changes i could be missing to provide? any help is appreciated

(P.S. i created all employees using admin account on the console and all changes to the employee details are managed through the admin account. Employees are only given limited access such as to submit and approve leaves. The employee users are unable to see their own profile settings, so possibility of them changing their user details does not exist. They can only reset their password using the reset password option during login.)