Octane, thats absolutely my experience for JET A-1 freeze points also. As you know, the fuel in the tank never fully equilibrates with OAT for the reasons given elsewhere in this thread. So the theory is that if the aircraft spent a considerable amount of time at -70 C or below the viscosity of the fuel increased to a point where fuel flow was compromised even if it was at a higher temperature when that actually happened, because of the lag between ice/wax crystals forming and them melting. I have no idea where that happened in the fuel supply chain.
I dont know if there was a 'Lo fuel temp' EICAS message and if there was, whether it was acted upon. I do know that after the wing tank was punctured on landing the fuel would rapidly equilibrate and you wouldn't notice any change in physical properties in the fuel by the time you got to the scene. I do think that the eight seconds is incredibly significant because it points to an uncommanded common mode fault that was not software related. I think the fact that the engines responded then spooled down is not inconsistent with the above.
Thats all I know or think. I'm going back into lurk mode, as I've got nothing else to add really. Guess we should all wait for the next bulletin. I do hope that the retention samples were properly taken and that there is a proper chain of custody in their analysis, because we really need to know the answer, or to exclude fuel as the cause.
Pinkman