When you say leaked, do you mean it's not closing and CO2 is passing through it when it should be off. (seen in a bubble counter as bubbles) OR it's leaking CO2 out of the solenoid?
If that's addressed to me, I meant passing CO2 when it should not have. I did not have the needle valve installed yet because I wanted make sure any debris was first flushed from the system. When on, the solenoid passed a blast of CO2. When off, it passed a small amount at 15 psi, which became rapidly greater as I increased pressure at the regulator.
If I'd had the needle valve installed before diagnosing the solenoid problem, I think I would have seen a similar bubble rate regardless of whether the solenoid was on or off. The leak was enough, and the flow restriction in a needle valve is so high, that it probably would have resulted in almost the same pressure at the needle valve input either way.