My disgust on the thought of eating something like that isn't a personal attack on you, but I'm sorry if my comment came off that way. It isn't that I never "cheat" or that I keep strictly Paleo, or that I judge you for your "cheats", it's just that most junk food stuff really gets me. If you had said Cheetos, a Big Mac, or Kit Kats, my reaction would be the same, as would it would be the same if my own mother had said that. My "cheats" are still generally quality foods, just ones that contain grains or beans. But your "cheats" are completely up to you and everyone has different cravings.
I haven't eaten a cake like that, but from the name it sounds like a quite sweet dessert. I don't know that the grains would be particularly bothersome unless you have an allergy/intolerance, but if you have been eating Paleo for a while, it could just be the sugar, not the corn grain. I think that a big load of sugar would be more likely to upset my tummy than some corn.