I think it’s the whipped cream. My sister loves whipped cream frosting so I make it a lot. It never really gets stiff like buttercream and it stays wet. Wet+fondant=sticky fondant. I usually use flavored Swiss meringue buttercream, it doesn’t really have a buttercream texture and flavor. Good luck 😊
Edit: I’ve never had a problem with condensation while refrigerating my fondant cakes (buttercream then fondant)
