My buddy had very similar thing happen. It was an oil line to turbo. The turbo oil drain line got cooked from excessive heat. It cracked and oil got everywhere. In your case, could it be consuming the oil through the turbo? Could run NA to narrow it down?
Idleing it is basically NA. And it still choo choo trains out of the breather when it’s hot. It’s not oil smoke it’s pushing combustion gas past the rings somewhere. Turbo life. It happens.