I believe the cracking pressure was set just a tad too light, I had the venturi open and the micro adjust wide open, this caused a free flow. I switched regs, closed venturi, and closed micro adjust, popped it and it stopped. Opened venturi, opened the micro adjust full open and reclosed half a turn and then switched to it. All good, just cracking pressure set too light, not icing. SP S600, but not really the regs fault, just misadjusted. I am confident that my breathing increased when I saw the ship, which likely initiated the free flow because it was breathing normally for the descent.
