Well, first off, you shouldn't do that with a 1911. That said, does the hammer follow with the grip safety released (ie the grip safety should be working blocking the trigger). If it (the hammer) doesn't follow with the grip safety blocking, the problem is likely to be trigger bounce (the inertia of the trigger is tripping the sear) if not, it's possible that there isn't enough engagement in the hammer hooks (which can be caused by wear induced by dropping the slide on an empty chamber). If it's the latter you need a new hammer, but have it checked by a good 'smith. Oh yeah, this can happen to ANY 1911 and has nothing what so ever to do with the ethnicity of the 1911. Another reputable 'smith out in the darkness of Bantario is Roger at Dark Int'l.
ETA: So all of you guys playing Steven Seagal in the bedroom QUIT DROPPING THE SLIDE ON EMPTY.
Further edited to add: if you want a gun to play action hero with buy a Glock. The 1911 prefers to be loaded and shot, not played with.