i am facing this issue with user-manager-6.0rc4-ppc . but it seems that it works if you clear your browser temp files and restart the system... but this is not viable option. I also notices that it occures when multiple sessions are open.
this can be achieved by assigning multiple profile to the user. Userman will automatically assign the profile based on sequence /priority we will assign and it will deactivate the profile once it has been expired.