Another comment:
“The only reason I have put a premature second stage engine ignition on the list is that the entire ascent is computer/ software controlled. There could have been a wrong number entered for certain events. It’s what downed a Delta 3 and an Ariane 5 launch...miss entered numbers. Now a misinformed computer could have caused all of the other possible events such as pyro-fasteners, over pressurized second stage tanks etc. We will know more once the press conference happens...and then it might be a week or two.”