So you have assumed that that particular telemetry was the first actual unusual event. How do you know there was not an undetected failure mode earlier? What is your evidence?
Well, nothing was reported. What evidence do you have of some other "anomaly"?
Certainly being hit by a missle wouldn't be an "undetected failure mode".
I mean, we don't know that someone didn't break into the airport, sneak up to the plane, and sabatoge the plane, but there's no evidence of it.
It was the first commented on, and the initial missile impact would be more than significant enough to comment on.
How do you know there was not an undetected failure mode earlier? What is your evidence?
Because I've been there and done that with things going "Ka-boom!" around me, some of them down to about one pound of Composition B (hand grenades).
Trust me, one will notice more than a pound of HE going off in contact or close proximity to one's aircraft, even if said aircraft is a 747. That event would have been commented on, most likely with some variation on the theme of "sacred fecal material."