New iPad 12.9 missing camera shutter sound

I set up two new iPad 12.9 devices yesterday. I've noticed that one of them does not have the camera shutter sound when tapping the button to take a picture. The device was originally set up from a backup of my Air 2. When I realized that the camera shutter sound was missing, I redid it and set it up as a new device. It made no difference. I've tried hard reset a couple of times and it has made no difference. I made sure that sound effects and volume were turned up all the way and, again, no sound.

All other sounds are present and working. I can go to the sounds in setup and play a bunch of sounds with no problem. When I press and hold the camera button to take multiple shots, I can hear a sound, but it is pretty muted.

This has to be some sort of software issue, because there is nothing mechanical going on. The pictures that I'm taking come out fine.

I really don't want to have to take this iPad back, because it has the best screen that I've ever seen. In fact if there's no way to fix it, I'll probably still keep it, unless it points to a hardware flaw of some kind.