When does Shipment Status - Tracking get triggered in OTM

Summary:

We are using Shipment Status - tracking as an triggering event in Shipment Event Tracker Agent to match and update the actual stop timings in Shipment stops

But it is not getting getting triggered got some of the shipments so Actual Arrivals and departures are not getting updated on the shipment stops

Can anyone let me know what can be the issue with this

Content (please ensure you mask any confidential information):

We are using Shipment Status - tracking as an triggering event in Shipment Event Tracker Agent to match and update the actual stop timings in Shipment stops