Agreed.
I wondered earlier if there was a pitch problem, and if there was then it almost certainly would have revealed itself only after Vr was called, by which point they were obviously well past V1 and therefore committed to the take-off.
There could well have been a serious brown trouser moment, while the 4 pilots tried to work out what the hell was going on as they accelerated down the runway - too late to RTO; and they eventually managed to haul it into to the air at the last moment.
They then might have convinced themselves that they must have done something procedurally wrong, and there was nothing faulty with the aircraft, so they continued their flight and perhaps did not put in a report, hoping it would not be spotted?