At what stage does the resource Alert for Pending Seat Acceptance trigger to the learner?

Summary:

We have created a Resource Alert for Pending Seat Acceptance but there is no alert triggered to the learner when the capacity of the offering is increased and schedule process - Process Learning Alerts is run.

Question: At what stage does this alert trigger to the learner? when the assignment status of the learner changes from Waitlist status to Pending Seat acceptance status?

Steps followed -

1. Create a course
2. Create an offering under the course with Capacity rules set as Maximum attendees = 1
3. Add a learner to the offering - L1
4. Add another learner to the offering - L2
5. L2 Assignment status = Waitlisted