I have a friend who loves to bake and she has made a couple of cakes from recipes that have been tried & true and both of them did the same thing yours did. Same recipe, same oven, same pan. The only thing I could think of was the size of eggs she was using. She says she always uses extra large, but I read somewhere recently that if an egg is called for in a recipe, then they mean large. I hope someone has the real answer, so I can help her out too.
Edited to add: This Betty Crocker website has some good info.
http://www.bettycrocker.com/products...oist-cakes/faq