I had the same problem.This exact thing happened to our '13, and it turned out that a portion of the underbody was improperly sealed from the factory. Took the dealership three weeks of troubleshooting to identify the issue, but it was an easy fix once they did.
Yes, they're pretty terrible. I suppose they don't have any incentive to provide good service when they're the only Ford dealer in the area.I had the same problem.
The dealer put the car through a car wash to find where the leaks were coming from. Your dealer sucks.