Funny then that when the preliminary assesment identified the possible cause (correctly) and advised that all Trent900 engines needed inspecting, RR very qickly said "Only the A variants need checking". Why - because the misaligned stub had been picked up in their QA processes and fixed in the B & C variants. This is no doubt a reasonably routine event when you roll out a new engine, and is part of the reason that RR certified the A variant for 2000 cycles, the B variant for 14000(?) cycles, and the C variant for unlimited cycles. The real issue is what (if anything) they told their service engineers about it, and whether their "power by the hour" arrangement with Qantas included disclosure or notification clauses about known defects.
And let's be clear - the engine shat itself in a big way and caused significant damage and impairment to the aircraft. Lucky it happened to probably the best Qantas crew you could assemble. If it was an Air France plane it would have been in the drink faster than you could say "Mon Dieu!"