I am having this notification issue with most of the apps like Instagram, Snapchat, sometimes WhatsApp too. The notification for these apps does not appear in notification centre, lock screen or banners. Steps I’ve tried:
1.) Checking the settings of notifications in general and as well as for apps individually.
2.) Re-install apps.
3.) Formatted my iPhone.
4.) Online technical assistance for iPhone.
None of it worked. And I don’t think apple is even considering this an issue. Forget fixing it, they aren’t even acknowledging it. If it is not fixed in the next update, I will be shifting to android. I hope everybody does the same, so that apple start taking its customers seriously.