Why is my "touch up inside" event for my UIButton not being called?

Aha, I got it. It turns out the subview which contained the button (along with the other controls) had a height of 740 and the button was at a Y of 781. Moving the button up fixed the issue. Since everything was displaying correctly, I didn't think to check the subview's height.

Make sure that your button is placed inside superView's bounds,
If a button is placed outside superView's bounds, the button will not clickable,
because of the implement of the hitTest function

I think you have placed your button on UIImageView, if so, you have to make UserInteraction enable for that UIImageView. Please check.