date time task event problem in 8.0 to 8.2

We have a project which is implemented in 8.0 and we are upgrading it to 8.2. We have a problem with date time task event. We have a date time event in the task which must complete task after 1 min. than created Date of task info.But it is not working properly. Task is not completed. It’s status is always active. Do you have any idea?