I create a voucher with 1 hour of time limit, limited usage 1, client duration and by usage is selected. So that i can save the  voucher time when i have something to do  . I use my phone stopwatch to monitor my hour of usage.  turn off my phone wifi i pause the stopwatch  I notice when i turn off and on my phone wifi  many times and go to other eap site. After an 2 hours of  internet browsing im still conected . The viucher time limit not expiring. After 1 day i can still connect to the hotspot.