I’ve had a couple of instances where I had trouble getting notifications working. Most recently when the app got switched to nabu, and prior to that when I switched to a new phone.
In both cases it was a lot of trial and error to get notifications working again. Not sure what fixed it but some combination of deleting the iOS integration, reseting push ID, and many restarts got it working again. It’s pretty hard to debug iOS notifications. This is the only trouble I’ve had with home assistant recently.