Well I don't actually think this reported aircraft ever deviated from its flight planned track. I think its more a case of one FIR not sharing the flight plan with other, and when asked where the next point would be the pilot read the legs page lat long that did not show the 30" (wont happen on a bus!!), when the controller noticed the difference in tracking he filed a report (perhaps he was australian ATC trained?).
But good on you for jumping to conclusions there Thazright. I am pretty sure there is a management job waiting for you ya muppet!!!
Don