I cant prove it... but I have noticed that my phone when I leave it alone does not do much if any notifications. But if I pick it up for a few mins and fiddle with it. Suddenly there are 2-3 notifications from applications that havent made a peep since yesterday but only after I turn the screen back off. Usually to tell me something very trivial. I suspect there is a background timeout that waits 1-2 mins after I set the phone down. Trying to get me to re-engage with the thing.