Brief question/note, and probably not relevant....
There's a mention of an abrupt change in tailwind as a contributing factor.
Could that have been accompanied by an abrupt decrease in OAT?
That would cause a drop in the speed of sound, hence an increase in Mach number for the same airspeed.
Just asking because we ran into the same thing with Concorde.
The problem wasn't recognised until the route proving, because the phenomenon doesn't really occur at higher latitudes.
The result of the sudden increase in Mach number was a quite unpleasant pitch excursion as the A/P tried to stay within the M=2.04 limit.
The problem was solved in the end by a major modification of the Max Cruise mode, with both A/P and A/T being made to "do their share" to keep the aircraft inside the limits.
CJ