there seems to be an issue with the OLD system and the NEW system.
I have 4 trackers. I added them all to a notification.
I used the new system to remove all notifications from one of the Trackers I continued to get notifications.
When I looked int the OLD system it showed a notifiaction with 4 devices still.
I have removed the device from it now and I hope that works.
You need to lok at how the notifications work bewteen the old system and new system with multiple devoices.