The left hand thing happened to me as well on my first day, but I haven't seen it since. Mine wasn't from holding anything, all I had to do was walk through a door and my left hand disappeared. Hopefully they fix common occurrences of it.
So far I'm loving the game, everything looks and feels amazing. I got my Index just before it came out, so the improved visuals are great. So many moments make you feel like you're actually inside a movie.