snapchat notifications don’t come through when phone is unlocked

I just upgraded to the newest IOS (unintentionally) and my Snapchat notifications are not coming through when my phone is unlocked. I have always had my phone on DND and want to keep it that way. All of my other notifications are coming through as normal and as they used to except Snapchat. I have all notification preferences set to how they’ve always been. They come through as they should when my phone is locked. Can anyone please help?