I'm not sure what I have changed but my notifications on lock screen have started doing strange things. When I get a text, for example, I get the notification and preview message on lock screen as I am supposed to. If I'm sitting at a desk and I can't get to the message right away I the notification set to only repeat once for that particular message. The screen will go blank but after a few seconds it comes back awake and vibrates with the message at the top again. It will continue to do this over and over again all day long until I finally open message. It will also do this with other notifications