Bearfoil remember that in Alt Law Vsw is based on an AoA value which is lower than V Aprot in Norm Law and if you drop into Alt Law at Hi LvL the warning can be triggered by turbulence or heavy handed inputs on the controls (less damping at altitude) especially if your at Turb speed. Its for this reason that Airbus suggest you cruise 4000 below your max alt for weight. So I would suggest that the 2 stall warnings early on were genuine.
The article in safety first explains all of this much better than I can.
Narval's advice about not changing anything is spot on. Once they'd lost the A/P if they'd simply disconnected the A/T, set crz pwr and held the attitude it would all have come back for them.