Continue forever? no. Be performed once at no cost? maybe. I'm kinda sceptical that a computation to which the 2nd law is indifferent would occur spontaneously

Continue forever? no. Be performed once at no cost? maybe. I'm kinda sceptical that a computation to which the 2nd law is indifferent would occur spontaneously without immediately reversing. The 2nd law is what determines the direction that things typically progress.