No one knows...
I’m reading “American Caesar” a book on MacArthur. China was allowed to strike Korea from Manchuria while the JCOS wouldn’t let him strike north of the Yalu. State Department was complicit. He was handcuffed. Now I’m right about where he was fired. The higher ups were simply scared of him. Success at Inchon did it. Truman flew all the way to Wake island to meet him just for political purposes.
Those who know don't talk.
Those who don't know, have no such restriction.