There Are some razors that just seem to have a proclivity to rust very easily. I've had a few. The important thing is to make sure the razor is dry, totally dry before putting it up. Some sterol or other protectant will keep the rust away.

I've had some razor's that I used one day and the next day there were traces of rust already. After those incidents I always put some sterol even if I'm gonna use it the next day.