I have not had luck refrigerating buttercream but I am wondering if it is because I live in such a warm humid climate. (I live near the ocean) I have tried to refrigerate a buttercream cakes, but when I take them out of the fridge, they sweat and get little beads of moisture on them. I have tried to refrigerate buttercream icing (wilton recipe) and if I let it come to room temperature to try to use it again, It sweats and breaks down.
I don't wrap my buttercream cakes, I place them in boxes.
If I keep my buttercream at room temperature, I have no problem with it. I also put my left over buttercream into the plastic tubs my shortening comes in and leave it out at room temperature. If it is for longer then 3 days, I usually pitch it, but I try to smell/taste to see if it is okay to use.
I hope this helps.