Fuel Aeration ??
The fuel system designers will have gone to a great deal of effort to prevent air entering the systems. Cannot imagine any possible entry point which would not have been leaking under normal fuel pressured operating conditions unless such a leak/s were contained within a fuel tank and hence undiscovered. Any air bubbles in the fuel at the input to the high pressure pumps could be expected to promote cavitation which will reduce pump output but only remotely possible below that being demanded by the engines at low thrust.
The AAIB is probably being simplistic in calling fuel vapourisation or partial vacuum at the HP pump inlets under cavitation conditions "aeration". Such conditions almost simultaneously in two seperate sytems is a very long shot.
I guess somone is rapidly assembling an instrumented test rig.
What a fascinating problem for our armchair Investigation Board to dwell upon and many pilots and engineers will benefit from their enhanced knowledge of jet engine fuel systems and fuel behaviour.
Missing from my know how and experience as a TP is the propensity of cold jet fuel to form vapour (not air bubbles) at the HP pump inlets at pressures close to a vacuum and can extensive vapourisation occur instantly to both damage the pumps and substantially reduce pump outputs?