Thanks a ton everyone for checking for me. I will add this to my list. I am using my own sleeves for the other cards (besides the heroes), so this will be an issue for me.
You may want to contact Megacon and let them know, they are doing replacement parts now and that sounds like something they could fix. If you don't want to go that route you could get some solid backed sleeves or sleeves with art on them to cover the back.