Test your notification events by right-clicking on them and selecting Test this event. VSys will describe the events filters and show you:
Seeing "removed x notifications as already notified"?
To avoid sending out the same notification over and over again, VSys tracks what notifications have been sent before. In this case VSys looked at the item in question - training record, assignment, application, what have you - and found a previous notification based on the same event (for example, "VSys Live Application") in the past, and so won't send it again here to the same recipient.
To see the notifications sent in regard to a specific item, right-click in that item in someone's profile and select See tracked changes or See notifications. VSys will pop up a list of the notifications it generated in the past.
Consider the event "Training statuses". We're allowing the Statuses Cancelled by volunteer, Failed and Registered. VSys will send a notification when someone is registered for the course. A few days later the volunteer cancels online, and VSys will not send out a notification about that. Why? Because this event in this subscription has already sent a notification, and VSys has no way of knowing that you meant that a change in status was enough to warrant a new notification. So what should we do? Create two different events:
Checking the box Allow re-notification for the same item after some period of time tells VSys to ignore any previous notifications based on this item, whether or not they were created based on this event.
Be careful with Allow re-notification...: if you set that to, for example, ten minutes, then these trainings will send out new notifications as often as every ten minutes - even though nothing has necessarily changed about those trainings!