Thanks for updating the thread @tf1962!

Ok I figured it out. Problem fixed. This has nothing to do with debug or release build configuration. UIView in question has children views that have userInteraction enabled only in debug mode. In both debug and release, the touch events are handled by the parent. I guess exclusiveTouch needs to be set on the view in the hierarchy that first intercepts the touch events even if it passes them up. In our case that's the parent in release mode but the child in debug.