Probably more due to them now having 24 Q400s at what, 2000hrs per year at least?
Thick end of 50,000hrs per year plus some engines around 10,000hrs = law of averages.
Q400 is finicky at best, especially the non Next Gen which the majority of the QF fleet are.
Not sure how many of these have been "engine go bang" instances, certainly the electric bits have bad days and the guys have a QRH for the light or message and they follow it. Remember this is QantasLink - independent thought is prohibited - QRH says shutdown, you shut down - or pineapples follow - had enough very good driver mates f@cked over for using common sense and good system knowledge.