Agree Capt Cu, the facts are this: after the MAS 744 took off the next schedule to depart a few minutes later called the tower to say that it looked like "black plastic" lying on the runway. Tower put a light aircraft and a formation of two (maybe three) Hunters into holding patterns whilst an inspection was made.
The "black plastic" could not have been missed by all the aircraft that took off before MAS, so it is most probable that the MAS 744 either exposed previous damage or opened a runway fault line. In any event accountability rests squarly with the management of the runway - ACSA.