When you create a task and put a due date on it, say 3rd of November, you get a notification about it on midnight of that day. However, if you have several tasks, all with the same due date, on midnight instead of getting a single notification, or even all the notifications at once you get them periodically.

So if i have 5 tasks for 3.11., I will get 2 notifications about it at 00:00, 2 at 00:01, and again one 00:02. It is very annoying that the phone keeps pinging about 'due today', especially as at that time I am in bed and i just see the phone going off again and again.