Haven’t had this issue at my place. At in laws there’s a bit of delay but not an hour long delay. It has to do with your internet connection. Check that first.
I did notice this issue a couple of times over the last couple of months and it is not my internet as I was viewing newer notifications and an older one would come through! Never did get to the bottom of it
My internet is pretty good ran speed tests outside a good distance away from mesh network. Up and down speeds seemed fine. The only solution I have is at expense of phone battery life never let the app go to snooze mode or whatever let stay on forever then notifications work. App seems flawed