it depends on your 'set fail' timer in timer options... your exit time will pause if you open the doors, but the set fail timer continues... if your set fail timer is quite close to the set time, then that'll is likely the issue... for example, if your exit time is 30 seconds, but you leave the door open for 15 seconds and take a further 20 seconds to leave, then your system will pausethe exit timer for that 15 seconds, but the set fail, if set for 30 seconds, will activate as that is continuos.. if your exit time is 30 seconds, then set fail should be at least 45 seconds, but adjusting it to 60 seconds could help.