PBL, together with what FlyingNewbie and bsieker said re T/L settings according to FDR and A/T and T/L settings, A/T disconnecting would have created the problem. As far as I've understood, it's common practice, maybe even SOP, to fly the airplane with A/T on until the RETARD callout?
Now, if it's true that the FDR shows the #2 T/L above idle, disconnecting the autothrust would have the engine rev up to that thrust setting (as has been said multiple times).
Again: I fully understand and agree that leaving one thrust lever above idle in the flare is counter-intuitive, but it seems that it has happened.
My whole point is that the sequence following from this is made possible by the way the AB systems work, and maybe by the fact that pilots are trained to accept the counter-intuitive fact that under normal operating conditions, the T/L setting has no direct relationship with the actual engine thrust setting.
All you AB pilots out there, hasn't that been counter intuitive to you when you got your first AB rating? It would seem so for me.
After all, what we call intuitive is often just our past experience that has gone subconcious.
pj