I am having this issue with all notifications, email, phone, Kuna, WhatsApp, gmail, etc. What happens is that once the screen/phone goes to sleep, notifications do not come through. If I take out the phone sometimes there is a notification icon in the top bar, but the audible sound is not working. As soon as I use my fingerprint to unlock the phone, the notification sound alerts go off. Very annoying as it worked perfectly up until now. If the phone was in my pocket and I got an email or text, etc., I would hear the alert tone and know to check. Now there is silence and unless I keep taking out my phone to manually check, I will not know I have anything waiting.