When brass gets cold it shrinks. That’s when your leak starts. I would would 1st check the yoke nut retainer face for any kind of scratch/damage. Next I would remove the yoke nut retainer, replace that oring against the body. Reattach the yoke nut with the new oring and tighten to the proper torque setting. I have seen divers strip out the treading of the 1st stage brass housing. Find a dive shop that employs a full time life support tecnition. Have done what I said and your problem is resolved. If that doesn’t do the trick. Then replace the yoke nut retainer because the face is damage/warped that you can’t see. Also don’t use grease on the tank o ring. It’ll collect dirt and you’ll then have two leaks