The biggest problem with deferring the Lobstacle to the AI is that you could have a roughly human-comparable AI which solves the Lobstacle in a hacky way, which changes the value system for the successor AI, which is then intelligent enough to solve the Lobstacle perfectly and preserve that new value system. So now you’ve got a superintelligent AI locked in on the wrong target.
The biggest problem with deferring the Lobstacle to the AI is that you could have a roughly human-comparable AI which solves the Lobstacle in a hacky way, which changes the value system for the successor AI, which is then intelligent enough to solve the Lobstacle perfectly and preserve that new value system. So now you’ve got a superintelligent AI locked in on the wrong target.