I was in a flat parking lot the first time it happened so can't blame the angle. Hopefully the dealer will figure it out.
The liftgate won't latch completely if you start the engine while the closing is in progress. This appears to be a standard phenomenon. If this isn't the source of your problem, then I agree it's an issue for the dealer.
2013 Sterling Gray Metallic Escape SEL 2.0L 4WD w/Equipment Group 302A, Panorama Roof, Ford OEM Cargo Area Protector, Ford OEM Splash Guards, WeatherTech All-Weather Floor Mats (front only), Ford OEM Center Console Tray, Aluminum Pedal Covers, Fitted LED DRLs