SAN DIEGO — The highest-ranking Marine officer bearing some responsibility for the fatal 2020 sinking of an amphibious vehicle off the coast of San Diego is being formally disciplined by the Marine Corps, the service said Wednesday. Maj. Gen. Robert Castellvi, who was the commanding general of the Camp Pendleton-based 1st Marine Division at the time of the accident, will not return to his current job as the Marine Corps inspector general. He also received what the Marines described as “adverse administrative action” — that is, he was “personally and formally” counseled by the commandant of the Marine Corps, Gen. David Berger. Castellvi failed to “properly train the Marines and sailors for whom he was entrusted” and inadequately evaluated the amphibious platoon before it was attached to the 15th Marine Expeditionary Unit, the Marines said.