How does Task/Appointment Reminder behaves?

Summary:

Users report they are receiving a lot of reminders that expected.

Content (required):

We are receiving reports from users that they are spammed with reminders although they only one task/appointment logged. In one of the report, a user received 155 reminders. We have temporarily disabled both the email and push notifications as it is currently being an annoyance to the user. But, they do somehow want a notification/reminder in the future.

Were the reports that we received an expected behavior of the task/appointment reminder? Can someone explain why this happened and what should I be looking for/at to correct this?