No, the two different electrician’s opinion is that it appeared to have started behind the breakers on the buss bar because a wire had gotten loose and heated up.
Was it one of the big wires from the meter ?
No, this appeared to be midway down the panel.
When I was a facility manager I used to hire a company to come in every few years and do a thermal
Infrared imaging scan on power panels and similar equipment.
They always found hot spots like wires loose or corroded, bad breakers, etc.
It was always money well spent.