Doze
Whilst in Autopilot, notice the oscillation of the THS, it varies 1-2 degrees very consistently, and smoothes when PF inputs NU. It also flies at three degrees NOSE DOWN during the same time frame. Stick obviously caged in spring tension.
Am I seeing some "Weather" reactions? Or an anomalous "Buzz"? Of course it is not flutter, but flutter does present that way.......