Since beta 4 update, for almost all apps (Messages, Whatsapp, Telegram, Messenger etc..) read notifications remain marked as unread, keeping the badge icons in the homescreen and even inside the apps messages/conversation stay as unread. 
A way to remove them is to manually mark them as read, but future notifications will stay where they are.
The only workaround is to reboot the iphone, but it's only a temporary fix. After some time the bug appears again.
	
		
			
		
		
	
				
			A way to remove them is to manually mark them as read, but future notifications will stay where they are.
The only workaround is to reboot the iphone, but it's only a temporary fix. After some time the bug appears again.