@Malibuflyer
I am confident that accident investigators don‘t rely on Flightradar24 e.a.
They get their stuff first hand from the respective ATC units.
I had a look at my last flight on FR24 and noticed the altitude seems to be off by quite a bit (on the low side), I suspect it is recording the pressure altitude rather than correcting it for barometric altitude. This would obviously need to be taken into account as pressure vs baro can be a few hundred feet apart, and in high pressure will suggest the aircraft was flying lower than it really was.