Pillsbury Muffin Mix Not Getting Crumb Texture On Pillsbury Cake Mix?

Not getting crumb texture on pillsbury cake mix? - pillsbury muffin mix

I have Pillsbury moist supreme cake mix (Chocalate one) in recent days, the same directions.when was found that crumb (like muffins.) Only the top n bottom of the cake, but not in the middle part. . I want the whole cake in Juz tilth, and roll the middle .... Chocalate was as a set .. is the humidity like that?