If the aircraft was misloaded, it would probably manifest itself on departure.
With an aft cg (out of limits aft that is) you'd get either a tail tip on the ramp, lack of nose-wheel steering authority during taxi or the aircraft trying to take off before VR. Going back to the ramp, the trained eye would see the nose-strut massively extended and wonder why...
I've no idea if the aircraft was full/empty or somewhere inbetween. Loadshift? Hmm. Full, that would be impossible, empty obviously impossible too. Assume it was partially loaded for argument's sake and also for argument's sake one ULD was not locked. This 3-4T ULD (being FEDEX I doubt it would be more) shifts a position or two (1 position = 10ft); would it make a difference balance-wise? I doubt anyone would even notice.