Baked a cake and it had a perfect 2 inch border all the way around. The center was done, but was a lighter color and much smoother. Baked in a 9x13 metal pan. Ive never seen this before. Taste was unaltered
Its really hard to say especially without a picture. Sounds like you oven might be need calibration. You might also try using 'cake belts'; you can buy some or make your owns to try. Just wet paper towels, fold to the 2" strips, wrap in foil then wrap that around your pan. This helps keep the metal cool a bit longer until the inner part of the pan heats up -- helps even out the baking.
It is possibly your recipe, but it could also help to use cake nails / heating cores in the middle of the pan.