Phil Gollin ...
I suspect the AAIB will be thinking, "let's not take our fences until we have to".
Meaning, there is a long way to go before a FINAL report is issued - possibly years. And during that time the AAIB and others will seek the answer to the riddle. And they know they must find the answer/cause.
Meanwhile other bulletins will probably be issued which will include operational changes to high altitude, low temperature flights. Expect the next before the northern hemisphere Winter.
Regards, Tanimbar