Not knowing the inside story but I would imagine that the stuff up is completely internal. What was that airframe doing after it would have returned from DPS? Jetstar often ferry empty planes around the sky so the decision to return it to base would have been made on just having it back in ML and bugger the pax. Jetstar flights are often delayed out of Melbourne because the only bloke certified to tow planes to the gate is busy loading bags onto a 787. Before you jump in the engineers are not allowed to do it due to contractual obligations. If you think things are bad at Jetstar then you can officially call yourself an optimist, they are much worse.