The only thing I can think of that would cause this problem, is DMC2 being powered from the captains side (Switching panel selection) followed by the the loss of AC Bus 1.
In this case, you would have exactly what is described above.
Interestingly, Airbus does not cover this situation in the FCOM's or the QRH.
It's something to be very concious of when operating with DMC2 MEL'ed. Since, if you then lost AC Bus 1, you would have a pretty black aircraft, but for the AC ESS BUS FEED fault light. Pushing that single illuminated button, brings light back to the Aircraft quite quickly.
Next ......
Hmmm, reference the following quote, isn't this the same company who flew a "three engine" Boeing 747 across the USA, then on to the UK just few months ago???.
"...OK, I' only going on the above info but: Night time, major unexplained electrical failure, held for 40 mins and then pressed on! Go ahead and flame me all you want guys but I have grave doubts about that decision. I trust that it was at least a full moon and VMC all the way to and at the destination (should it have re-occured)..."