It's normal. If parked headed downhill, it will usually run down the A-pillar. If parked headed downhill, it will usually run down a rear corner. My salesman told me about it during the orientation.
The higher the humidity, the more the A/C will extract from the air as it flows across the evaporator. Same as the A-coil in your furnace at home that usually runs down a tube to the closest floor drain.
Glass half full or half empty to an engineer is simply a glass that was over designed.
PM me for sale info on my 2011. SOLD!