How would a helicopter deal with auto rotation when it transports a hanging payload?
In theory, with that load, the rotor revs will be higher during the descent, and releasing the load just before flaring will give the pilot more rotor energy to control the aircraft with the collective in the last stage of the landing.

But it would be more prudent, in my opinion, to release the load as soon as possible. After all, in any dead stick landing, the lighter the aircraft, the better...