I don't think this is a bug. If the sim places the food prep board on a side slot on the counter, it isn't going to recognize that the sim can't stand and prep there unless they physically can't stand there (if a wall or another counter is in the way.) Since your sim can stand on the platforn and it isn't too far away from the counter surface, you can still use it but it cant make the sim bend over more than the ordinary animation. This would happen if you sized down a counter too. Its random whether your sim places it on a front of side counter slot if both are available for use.
