One problem related to wiper has been reported for the 2015 Ford E-350. The most recently reported issues are listed below.
The windshield has started to crack on the left (driver's) side. There is no indication of impact. The crack starts about 2 feet up at the edge of the glass, extends across the windshield a few inches and then turns down. It has continued to slowly grow. I believe this is a defect - possibly stress related. I have seen dozens of others reporting the same problem.