If i swipe super fast i can't leave introduction view. In your example you it works well. Maybe it's appear because i add MYBlurIntroView to "window" in app delegate?

MYBlurIntroductionView *introductionView = [[MYBlurIntroductionView alloc] initWithFrame:self.window.bounds];
[self.window addSubview:introductionView];

See video
https://www.dropbox.com/s/dkkeczdzcl9c28o/blurbug.mov?dl=0