OMG, mine had a water leak too. The tech at the dealership said they installed the cabin vents under the rear window incorrectly. They had to remove the bed of the truck, remove the rear seat, the carpeting etc. to fix it.
My 2020 Ranger is making the same noise. Very annoying. It goes into the dealership next Tuesday. I will post what the dealership finds. It had better not be "just live with it, its normal". The truck has already been in the dealership twice for warranty fixes. First was a missing bold...
Problem Resolved: The Ford dealer's tech removed many parts of the trucks interior (passenger and driver pillars, rear seat belts, rear seat, cabin to outside cab vents, carpet from under the rear window) and noise remained. Tech then put the truck in the air and discovered that "the noise was...