The contact owns a 2019 Buick Cascada. The contact stated that the rear windshield was separating from the convertible top plastic frame. The contact stated that the rear glass was pushing upward and out of the frame. The contact had called a dealer and discussed the failure and was advised that the manufacturer had issued Technical Service Bulletin: 17-NA-216 for the separation of the rear glass of the convertible top. The contact was advised by the service department that the repair would not be performed by the dealer. The vehicle was not repaired. The manufacturer was informed of the failure and referred the contact to the NHTSA Hotline to report the failure. The failure mileage was approximately 53,000.