I still don't see the answer to this. Did the power reduce, or were the flaps retracted prematurely? The later seems more likely as other protections are in place to cause a stall recovery. The power reduction is quite noticable and would get the crews attention rather quickly whereas a premature flap retraction would be more subtle IMO. Having experienced the latter in a MD11 once upon a time it remains etched in my memory. Either way it appears they handled it well.