This is a Rumour Network, so here goes.
The latest I've heard is that ATSB findings, point to a flex plate or yolk having broken. This would overspeed the tail rotor and underspeed the M/R. HM looks like they may be in some striff if this is true. There is a meeting soon to make public their findings.
This will take pilot error out of the equation.
Maybe you did it right Charlie...........
