We still have the QF RB211/747 SFO "explosion" and return to SFO (31 Aug), involving the IPT - it shed its blades, and thus the disc did not burst. I've heard claims of "no connection to the Trent events", but no detailed or convincing substantiation of that claim.
Further, it would be pretty hard for QF #2 Trent to encounter volcanic ash when #1, #3 & #4 and the airframe itself show no such distress signature. (I say no distress, because if ash HAD BEEN a factor, R-R would have immediately posited this for whatever commercial value could be gained).