Single VI,
Is this a new pistol? If not or maybe even so, it should go back for FACTORY repair. If the trigger isot being touched and the hammer falls to half cock when the slide is released, the sear-hammer-disconnector have issues; potentially dangerous issues. If you can locate a reliable and knowlegeable gunsmith, that truly knows the 1911, have him look at it. Historically with the 1911's that I have seen with issues, they were used, and a shade tree gunsmith diddled with something they knew nothing about.