App getting rejected because a bug I cannot recreate

My game has an "Exit" button in the intro screen that allows you to quit. I submitted an update to the game and the app review is saying when they click "exit," that it goes to a grey screen.

I cannot re create this. I've played it in a guest account in a "minimally privileged environment" yet it does not happen for me.

The button calls [NSApp terminate:self];

Is there any reason this might happen? I can't re create it. What should I do if I cannot? I am at an impasse here.