Users are not disconnected when their logons expire.
Disconnects occur after the scheduled disconnect time.
The 10 minute countdown prior to disconnect is not scheduled to run until one minute before the disconnect time. Several timers are not started and reset on time. This problem may be more evident for those connecting with guest sessions. This problem was corrected in the latest U.S. Service Pack for Windows NT version 3.5. In User Manager for Domains you can limit users to certain logon hours.