After a recent update, when contacts only calls come in while Do Not Disturb is turned on, I no longer see any notifications. I hear my phone ringing, but the display is blank. When I log onto the phone, the call app is not in the foreground. I have not made any setting changes that I'm aware of. Any thoughts?
if the phone updated recently then I would try to clear cache first to see if that helps, in addition to reboot. Sometimes it fixes the little stuff that just didn't apply correct the first time.
If it doesn't work, then the simplest thing to do is submit error report to Samsung Members after reproducing the issue or when you notice it happen again.