Late notifications on IPhones

Just started with HA, so I have some noob questions.

I have HA green which is running fine. In our household we have 4 iPhones and I set them all up with different automations and warnings, but I notice that the alarms are far from instant. I will get notification that the kids arrived in school 30 min later than they actually were. I’ll get a “home is empty” notification 15-20 min after the fact.
Is this normal? Should they not be fairly instant?
Did I do something wrong?