... or simply being constantly told during training "You can't stall an Airbus." as an absolute statement, reinforced by full back & side stick climbs at the lowest possible speed in the simulator to demonstrate "How the aircraft won't let you stall
That might be an (far fetched) explanation for the initial pitch up. Maybe the PF had a reflex action and applied a kind of windshear/terrain avoidance maneuvre. But after a few seconds it should be clear that that is not working.
I wonder in what state the aircraft was when the AP dropped out. Was it pitching down, or up? That's crucial information.