Are you sure your device wasn't just not loading it properly? I searched up if there were white blocks in Pokemon Shuffle, and nothing came up. I'm almost sure one of these two things happened; your device just didn't load completely; or it's an unknown glitch.
I'm almost sure it's the former, if this was a glitch, it would probably be a known thing. So, I'm leaning towards the theory that the game just didn't load up fully and you were left with a few blank areas of your screen.