In all this to-ing and fro-ing as to what might have changed on the fleet since this incident a couple of thoughts occur to me.
We know for an absolute fact that the US undemanded departure from flight did take place and, thankfully, all lived to tell the tale. So......
Has it ever happened since in their fleet?
As there was no cause found, did they carry out any mods to the aircraft as a result to try and prevent further occurences?
If they did modify the aircraft were those mods flowed across the Atlantic to the RAF Fleet?
The US response to this may help answer the questions being asked by JP and others.