Getting notifications from friends facebook posts?

I'm having a problem with facebook notifications. Ever since I got an iPhone last week, I'm getting delayed updates about friends facebook posts. Several days after a friend makes a status update, I get a notification saying that they have a new post. I have checked my notifications settings, and it's only happening from random friends. None of them are in my close friends list. And my close friends list has notifications turned off anyways. Does anyone know why I would have this issue?