Ive had that happen and i suspect its because i edited where it goes on my foot? but i can't prove that now. Anyway, put on another pair of shoes by dbl clicking a pair from inv to replace them and then after those rez try putting them back on by dbl clicking again from inv and they should be placed correctly. I had to go through that routine a couple times until SL learned where the shoe belongs and it hasnt happened in a while now.