Have DH check to see if the shelf you used is bent in the middle. That happened to me. There was a bend in the middle and cake came out lopsided as a result. I used a two foot long level to check the shelf and it showed as being level because the level spanned the dip in the middle and rested on the level parts of the shelf on the two sides.
Take the shelf out of the oven and lay it on the kitchen counter. It should lay flat with no rocking back and forth. Turn it over and try again.
Another question - are you using a convection oven?
"If you want to make an apple pie from scratch, you must first create the universe." -Carl Sagan