I would assume it drains into the tray underneath the car as per the 981. With that if I left it running on a slight forward tilting slope & on a hot day then eventually condensate would start spilling over the leading edge. There was a drain hole underneath but dependant on the car angle it wasn't always sufficient for the amount of condensate produced. It sounds like it's most likely that the small puddle is merely condensate. I often mop up puddles off the garage floor from both the BMW & my 718 without even a second thought.