Of course we can't jump to conclusions, the answers will come in the fullness of time, but abrupt pitch ups are not unknown.
24 SEP 1994 - Tarom Flight 381 approach to Paris-Orly Runway 26 and the captain was at the controls. He decided to perform an automatic approach and landing. The flight crew started to put the aircraft into the approach configuration, with slats and flaps at 15/0 at 10.42:05, then at 15/15 at 10.42:53. The landing gear was extended at 10.42:57. Approaching the OYE beacon at indicated speed 250 kt and heading 325, before lining up with the runway, the Captain noted that the aircraft was not capturing the ILS glide slope automatically. He disconnected the AP and continued the approach on manual control, keeping the Autothrottle in operation. As the aircraft descended through 1,700 feet, at 10.43:22, with a speed of about 195 knots, the Captain asked for flap extension to 20 . The VFE, the speed limit authorized for this new configuration, is 195 knots. When the flap control was set to 20 , the thrust levers advanced and engine thrust increased. The flight crew countered the nose-up effect resulting from the increase in thrust by using the pitch controls, with the auto-throttle (ATHR) remaining in automatic mode. The throttle levers were then quickly brought back to the idle position. At the same time, the trimmable horizontal stabilizer started to move in a nose-up direction. The nose up effect that resulted was countered by the flight crew through gradual nose-down action on the elevators. When the trimmable horizontal stabilizer reached its maximum nose-up value and the elevators also reached their maximum nose down value, the throttle levers, according to the FDR readout, moved rapidly to their stops. In a few seconds, the flight path started to rise and the pitch attitude went to 60 . Witnesses saw the aircraft climb. It banked sharply to the left and the right and stalled before adopting a strongly negative pitch attitude (-33 degrees) towards the ground. The maximum altitude reached was 4,100 feet, while a minimum indicated speed of 35 knots was recorded. The stall and ground proximity warnings sounded during the descent. The flight crew managed to regain control of the aircraft, with the lowest point being around a height of 800 feet, that is 240 meters from the ground. The flight crew then performed a visual circuit, followed from the tower by the controller. The second approach was made with a configuration with slats and flaps at 20/20. Landing took place at 10.52:25.
And many more.
FAA human factors report "The Interfaces Between Flightcrews and Modern Flight Deck Systems"
http://ocw.mit.edu/NR/rdonlyres/Aero...0/interfac.pdf