I haven't pinpointed exactly why and when, but I've noticed that I sometimes don't receive prayer request notifications for several days in a row. When I realize I haven't seen one for a day or two, I will open the app and then I'll start receiving them consistently again. If I don't open the app, I won't receive notifications until I do again. I think it might relate to when I re-start my phone, and it's like the app doesn't re-activate that feature until I open the app.
I'm using AC Central on a Samsung GS8 that I keep updated, and I'm happy to experiment to help figure out what might be happening.
SUGGESTION: include a field in this interface to register the phone hardware we're using
Customer support service by UserEcho