I suspect this has to do with server requests throttling, and then the notification process never gets triggered again--and the rest of the requests don't even attempt to get sent.
It is no longer guaranteed that the server will provide inventory information for every request; should the server choose to throttle a particular request, events indicating availability of inspection data will not fire..
I suspect this has to do with server requests throttling, and then the notification process never gets triggered again--and the rest of the requests don't even attempt to get sent.
https://wow.gamepedia.com/API_NotifyInspect