[ydoucare]

I have this same problem. However, alarms used to work perfectly fine, then just out of nowhere it does what you describe. Alarm goes off, screen turns on as if there is a notification, but the notification does not pop up on the bottom. I have to tap the icon at the top on the taskbar, then tap the alarm icon, then the notification appears where I can hit dismiss at the bottom.

EDIT: I got the notification to pop back up by go into settings/sounds & notifications/notifications tab, then select reminders, and recheck the "Display message on screen" box.