At the third stroke ...
The time will be ... Whatever that particular 'system' is using.
I would expect ACARS, r/t recording, radar recording and indeed the aircraft to all be working to the same time, properly synchronised with an atomic clock somewhere. But then again, when trying to determine a sequence of events by reference to possibly different time-stamps ...
Just a passing thought, as the sequence of events seems to be being regarded as an absolute.