A task does not run at the scheduled time if another instance of it is already running when the schedule tries to start the task. For example, you schedule a task to run every 5 minutes. The first task starts at 12 p.m., but does not complete until 12:06 p.m. The second instance of the task does not run at 12:05 p.m. because the first instance has not completed.
starts the next task at 12:10 p.m.