Do Not Disturb and missed call log

I'm using an iPhone SE running iOS11.2

When I set the iPhone to "Do Not Disturb", and someone calls me, not only am I not disturbed, but also there is no record of their call in the missed call log, so I have no way of knowing if someone has called when the phone is set to "Do Not Disturb" unless they leave a voicemail.

I've been on to Apple Care about this, and got the standard "you need to set your iPhone up as new" routine. Obviously that's a hassle I'd rather avoid, so I wonder if anyone else has had this issue, and what you've tried to remedy it.

Thank you.