I have a cake recipe, that is close to WASC that I've used many times with success. For some reason when I baked the cake today, it seemed to bake ok, a bit uneven, but then after cooling in the pan, got all shriveled up! This happened twice today with two different batches. Any clue why this is happening or how I can fix it? Thanks.

Do you add any leavening? Could it be old? Or maybe if you use mixes they could be old?