Same pistol, SP01 safety model, similar problem, probably went unnoticed earlier.
With all the CGW parts, hammer, short rest disco, (oem sear), from fully decocked, I can fire double action, as well as only get the hammer to stay in half cocked position, if i dont pull the trigger fully back to the breaking point. Previouslt, I could get it to stay in SA position, which was fixed by working on the disco.
SA is fine. Half cock onwards is fine.
Need advise please.