While I haven't done anything scientific to nail down the cause, I thought maybe someone else may have noticed this issue. I've noticed this with iMessages especially, could happen with SMS as well. I haven't noticed it with other notifications either, of course that doesn't mean it doesn't happen. It doesn't happen all the time either. Can this post get any vaguer? At times I can get an iMessage from someone and several minutes have elapsed and I leave it on the lock screen. If something else comes in, email, another message, whatever, I look to see how long ago the original iMessage came in and it will say one minute. I know that isn't right since my three message reminders have sounded so it's at least three minutes. Some have been well over 10 minutes and I know this because of something I'm doing at work takes that long. Anyone else notice this?