Basically, something about approaching level attitude made PF pull up. It happened at a/p drop, and prior to STALL warn. (Both times).
Fear of overspeed? Possibly. I would not eliminate a/c behaviour. I say again, YAW? Bobbing, wing drop? To indict the PF without eliminating a/c damage or unflyability is wrong.
Directional handling problem is known. Captain mentions Rudder, and PNF says: "WATCH your Lateral". These two guys were not flying, but were seemingly content that PF was, so there may have been a problem undisclosed by BEA.
What would cause the a/c to slew about as she exits MUSH? It would be premature to mention, but some possibilities of handling problems v/v heading exist.