This happened a few times on iOS 11.0 but it’s happening a lot more now on iOS 11.1. Occasionally the lock screen/notification screen will just be blank and not show notifications or the time. I will restart my phone or hard resets it and it will fix it but after 10 mins of usage it will revert back to the blank notification screen. Has anyone else had this and found a permanent fix? Sorry if it’s been covered before but I haven’t found it.