One reason I supported the MR separation idea was this paragraph from the linked newspaper report in post #19
A major air and sea search operation spotted the tail rotor of the aircraft before 9am Saturday and the main airframe was sighted 30 minutes later, the Australian Maritime Safety Authority (AMSA) said.
it seems strange that they use the phrase main fuselage without commenting on the main rotor when they have specifically mentioned the tail rotor.
A TR assembly won't float by itself but could if still attached to the tail boom - if the tail boom has detached from the main fuselage and there is no mention of the MR then it supports the idea of MR separation.
I still think that a combination of the poor references and the hideous turbulence are a perfect recipe for overcontrolling and creating a negative G situation that is so bad for teetering head helicopters.
Just before the data drops off a cliff there is a rapid climb which could result in a 'pushover' at the top leading to the aforementioned mast bumping.